B-PROG2 Materiály 2019

Materiály z roku 2019

/*Globalne a lokalne premenne*/

#include <stdio.h>

//globalna premenna: kazdy ju moze citat a modifikovat
int x = 3;

//void: bezhodnotovy typ
void fun1(void)
{
	printf("Fun1: %i\n", x);
}

void fun2(int x)
{
	//lokalny parameter x nahradi globalnu premennu x
	printf("Fun2: %i\n", x);
}

int main()
{
	int x = 2;
	//lokalna premenna x nahradi globalnu premennu x
	
	printf("main: %i\n", x);
	
	//TODO: co sa zmeni, ak dam fun1(x), fun2(x)?
	fun1();
	fun2(7);
	
	return 0;
}

/*Globalne a lokalne premenne*/

#include <stdio.h>

//globalna premenna: kazdy ju moze citat a modifikovat

int x = 3;

//void: bezhodnotovy typ

void fun1(void)

{

printf("Fun1: %i\n", x);

}

void fun2(int x)

{

//lokalny parameter x nahradi globalnu premennu x

printf("Fun2: %i\n", x);

}

int main()

{

int x = 2;

//lokalna premenna x nahradi globalnu premennu x

printf("main: %i\n", x);

//TODO: co sa zmeni, ak dam fun1(x), fun2(x)?

fun1();

fun2(7);

return 0;

}

/* Demo01: Celocislene delenie */
#include <stdio.h>

int main( )
{
	int a, b, c;

	while ( 1 == 1 )
	{
		printf("Zadaj 2 cisla:");
		scanf("%d", &a);
		scanf("%d", &b);
		
		if (b == 0)
		{
			return -1;
		}
		
		c = a/ b;
		printf("%i / %i = %i\n", a, b, c);

		c = a % b;
		printf("%i mod %i = %i\n", a, b, c);
		
	}
    return 0;
}

/* Demo01: Celocislene delenie */

#include <stdio.h>

int main( )

{

int a, b, c;

while ( 1 == 1 )

{

printf("Zadaj 2 cisla:");

scanf("%d", &a);

scanf("%d", &b);

if (b == 0)

{

return -1;

}

c = a/ b;

printf("%i / %i = %i\n", a, b, c);

c = a % b;

printf("%i mod %i = %i\n", a, b, c);

}

return 0;

}

/* Demo02: Floating point delenie */
#include <stdio.h>

int main( )
{
	double a, b, c = 3.4e-3;

	while ( 1 == 1 )
	{
		printf("Zadaj 2 cisla:");
		scanf("%lf", &a);
		scanf("%lf", &b);
		
		if (b == 0.0)
			return -1;
		
		c = a / b;
		printf("%lf / %lf = %lf\n", a, b, c);

		//c = a % b;
		//printf("%lf mod %lf = %lf\n", a, b, c);
		
	}
    return 0;
}

/* Demo02: Floating point delenie */

#include <stdio.h>

int main( )

{

double a, b, c = 3.4e-3;

while ( 1 == 1 )

{

printf("Zadaj 2 cisla:");

scanf("%lf", &a);

scanf("%lf", &b);

if (b == 0.0)

return -1;

c = a / b;

printf("%lf / %lf = %lf\n", a, b, c);

//c = a % b;

//printf("%lf mod %lf = %lf\n", a, b, c);

}

return 0;

}

/* Konverzia datovych typov:
   explicitna: operator (TYP)
   implicitna: 
     podla pravidiel zo standardu: 
	   a) na spolocny vacsi typ
	   b) podla typu premennej, kam sa zapisuje
 */
#include <stdio.h>

int main( )
{
	int a, b, c;
	double x, y, z;

	while ( 1 == 1 )
	{
		printf("Zadaj 2 cisla:");
		scanf("%d", &a);
		scanf("%d", &b);
		
		if (b == 0)
			return -1;
		
		c = a / b;
		printf("Celociselne: %i / %i = %i\n", a, b, c);

		c = a % b;
		printf("Zvysok: %i mod %i = %i\n", a, b, c);
		
		//x = (double) a; y = (double) b;
		//z = x / y;
		z = a / (double) b;
		
		printf("Necelociselne: %.0lf / %.0lf = %lf\n", 
		                      (double)a, (double)b, z);
		
		z = (int) (z+0.5);
		printf("Zaokruhlene: %lf\n", z);
		
	}
    return 0;
}

/* Konverzia datovych typov:

explicitna: operator (TYP)

implicitna:

podla pravidiel zo standardu:

a) na spolocny vacsi typ

b) podla typu premennej, kam sa zapisuje

#include <stdio.h>

int main( )

{

int a, b, c;

double x, y, z;

while ( 1 == 1 )

{

printf("Zadaj 2 cisla:");

scanf("%d", &a);

scanf("%d", &b);

if (b == 0)

return -1;

c = a / b;

printf("Celociselne: %i / %i = %i\n", a, b, c);

c = a % b;

printf("Zvysok: %i mod %i = %i\n", a, b, c);

//x = (double) a; y = (double) b;

//z = x / y;

z = a / (double) b;

printf("Necelociselne: %.0lf / %.0lf = %lf\n",

(double)a, (double)b, z);

z = (int) (z+0.5);

printf("Zaokruhlene: %lf\n", z);

}

return 0;

}

/* Demo03: Rozne celociselne typy */
#include <stdio.h>
#include <stdint.h>    // doplnkove definicie typov
#include <limits.h>    // pomocne konstanty - rozsahy typu

//vlastna definicia typu:
typedef unsigned short int word;

int main( )
{
	int                iP1  = -1;
	short int          siP2 = 100000;         //pretecenie
	char               cP3  = 65;             //cislo aj znak (default: ASCII kodovane)
	unsigned long int  ulP4 = 0xdeadbeef;     //hexa zadana konstanta 
    unsigned long long llP5 = -1;             //int sa da vynechat, -1 sa skonvertuje na unsigned
	word               wP6  = 0100;           //nas vlastny typ, osmickova sustava 
    int64_t            qwP7 = -1;             //alternativna definicia z stdint.h
        
    //TODO: priradit spravne format stringy
    printf("1. %i, size = %iB\n",  iP1, sizeof(iP1));
    printf("2. %i, size = %iB\n", siP2, sizeof(siP2));
    printf("3. %i, size = %iB\n",  cP3, sizeof(cP3));
    printf("4. %i, size = %iB\n", ulP4, sizeof(ulP4));
    printf("5. %i, size = %iB\n", llP5, sizeof(llP5));
    printf("6. %i, size = %iB\n",  wP6, sizeof(wP6));
    printf("7. %i, size = %iB\n", qwP7, sizeof(qwP7));
   
    //TODO: ostatne typy
    printf("Hranice int: od %i do %i\n", INT_MIN, INT_MAX);

    return 0;
}

/* Demo03: Rozne celociselne typy */

#include <stdio.h>

#include <stdint.h> // doplnkove definicie typov

#include <limits.h> // pomocne konstanty - rozsahy typu

//vlastna definicia typu:

typedef unsigned short int word;

int main( )

{

int iP1 = -1;

short int siP2 = 100000; //pretecenie

char cP3 = 65; //cislo aj znak (default: ASCII kodovane)

unsigned long int ulP4 = 0xdeadbeef; //hexa zadana konstanta

unsigned long long llP5 = -1; //int sa da vynechat, -1 sa skonvertuje na unsigned

word wP6 = 0100; //nas vlastny typ, osmickova sustava

int64_t qwP7 = -1; //alternativna definicia z stdint.h

//TODO: priradit spravne format stringy

printf("1. %i, size = %iB\n", iP1, sizeof(iP1));

printf("2. %i, size = %iB\n", siP2, sizeof(siP2));

printf("3. %i, size = %iB\n", cP3, sizeof(cP3));

printf("4. %i, size = %iB\n", ulP4, sizeof(ulP4));

printf("5. %i, size = %iB\n", llP5, sizeof(llP5));

printf("6. %i, size = %iB\n", wP6, sizeof(wP6));

printf("7. %i, size = %iB\n", qwP7, sizeof(qwP7));

//TODO: ostatne typy

printf("Hranice int: od %i do %i\n", INT_MIN, INT_MAX);

return 0;

}

/* Demo04: Floating point typy */
#include <stdio.h>
#include <float.h>

int main( )
{
	float  fx = 0.01;
	double dx = 0.01;
 
    printf("The maximum value of float = %.10e\n", FLT_MAX);
    printf("The minimum value of float = %.10e\n", FLT_MIN);

    printf("The maximum value of double = %.10e\n", DBL_MAX);
    printf("The minimum value of double = %.10e\n", DBL_MIN);

    printf("Float : %0.3f = %0.30f\n", fx, fx);
    printf("Double: %0.3lf = %0.308lf\n", dx, dx);

    return 0;
}

/* Demo04: Floating point typy */

#include <stdio.h>

#include <float.h>

int main( )

{

float fx = 0.01;

double dx = 0.01;

printf("The maximum value of float = %.10e\n", FLT_MAX);

printf("The minimum value of float = %.10e\n", FLT_MIN);

printf("The maximum value of double = %.10e\n", DBL_MAX);

printf("The minimum value of double = %.10e\n", DBL_MIN);

printf("Float : %0.3f = %0.30f\n", fx, fx);

printf("Double: %0.3lf = %0.308lf\n", dx, dx);

return 0;

}

/*Ukazka: je potrebne mat spravne typy pri stdio funkciach
     ak zle printf: hodnoty sa nespravne vypisu
	 ak zle scanf: hodnoty sa nespravne nacitaju
	               moze dojst k padu programu (nedostatok pamate) 
 */

#include <stdio.h>

int main()
{
	int a, b, c;
	double x, y, z;
	
	printf("x? ");
	scanf("%lf", &x);
	
	a = (int)x;
	
	printf("x %%i: %i\n", x);
	printf("x %%f: %lf\n", x);
	printf("a %%i: %i\n", a);
	printf("a %%f: %lf\n", a);
	
	
	return 0;
}

/*Ukazka: je potrebne mat spravne typy pri stdio funkciach

ak zle printf: hodnoty sa nespravne vypisu

ak zle scanf: hodnoty sa nespravne nacitaju

moze dojst k padu programu (nedostatok pamate)

#include <stdio.h>

int main()

{

int a, b, c;

double x, y, z;

printf("x? ");

scanf("%lf", &x);

a = (int)x;

printf("x %%i: %i\n", x);

printf("x %%f: %lf\n", x);

printf("a %%i: %i\n", a);

printf("a %%f: %lf\n", a);

return 0;

}

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

//pozn.: nie je to presne, zavisi na nasom programe...
#define FPS          30

// Podmieneny preklad: verzia pre WINDOWS sa lisi od LINUX verzie
//    - pomozeme si s makrami a podmienenym prekladom:
//       Sleep/usleep uspi program na dany pocet ms
//       premazanie obrazovky -> bud program cls, alebo tzv. escape sequence [2J
#ifdef _WIN32
 #include <windows.h>
 #define PAUSE()              Sleep(1000/FPS)
 #define CLEAR_SCREEN()       system("cls")
#else
 #include <unistd.h>
 #define PAUSE()              usleep(1000/FPS)
 #define CLEAR_SCREEN()       printf("\x1b[2J");
#endif

void vypis_obrazovky_old(int pozicia)
{
	printf("%*c\n", pozicia, 'o');
	printf("%*c|-\n", pozicia-1, '-');
	//printf("%*c\n", pozicia, '|');
	printf("%*c \\\n", pozicia-1, '/');
	
}

#define RIADKY 20
#define STLPCE 60

int je_ramcek(int riadok, int znak)
{
	if ( riadok == 0 || riadok == RIADKY - 1 )
		return 1;
		
	if ( znak == 0 || znak == STLPCE - 1 )
		return 2;
	return 0;
}

int som_vnutri_kruhu(int riadok, int znak, int polomer)
{
	int dx = znak - STLPCE/2;
	int dy = riadok - RIADKY/2;
	double distance = sqrt(dx*dx + dy*dy);
	return distance <= polomer;
}

void vypis_obrazovky(int pozicia)
{
	int riadok, znak;
	
	for (riadok = 0; riadok < RIADKY; riadok++)
	{
		
		
		for (znak = 0; znak < STLPCE; znak++)
		{
			if (je_ramcek(riadok, znak))
				printf("+");
			else if (som_vnutri_kruhu(riadok, znak, pozicia))
				printf("*");
			else
				printf(" ");
		}
		
		printf("\n");
	}
	
}

int main()
{
	int pos = 10;
	while (1 == 1)
	{
		vypis_obrazovky(pos);
		
		
		pos += 2*(rand()%2)-1;
		
		PAUSE();
		CLEAR_SCREEN();
	}
	
	
	return 0;
}

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

//pozn.: nie je to presne, zavisi na nasom programe...

#define FPS 30

// Podmieneny preklad: verzia pre WINDOWS sa lisi od LINUX verzie

// - pomozeme si s makrami a podmienenym prekladom:

// Sleep/usleep uspi program na dany pocet ms

// premazanie obrazovky -> bud program cls, alebo tzv. escape sequence [2J

#ifdef _WIN32

#include <windows.h>

#define PAUSE() Sleep(1000/FPS)

#define CLEAR_SCREEN() system("cls")

#else

#include <unistd.h>

#define PAUSE() usleep(1000/FPS)

#define CLEAR_SCREEN() printf("\x1b[2J");

#endif

void vypis_obrazovky_old(int pozicia)

{

printf("%*c\n", pozicia, 'o');

printf("%*c|-\n", pozicia-1, '-');

//printf("%*c\n", pozicia, '|');

printf("%*c \\\n", pozicia-1, '/');

}

#define RIADKY 20

#define STLPCE 60

int je_ramcek(int riadok, int znak)

{

if ( riadok == 0 || riadok == RIADKY - 1 )

return 1;

if ( znak == 0 || znak == STLPCE - 1 )

return 2;

return 0;

}

int som_vnutri_kruhu(int riadok, int znak, int polomer)

{

int dx = znak - STLPCE/2;

int dy = riadok - RIADKY/2;

double distance = sqrt(dx*dx + dy*dy);

return distance <= polomer;

}

void vypis_obrazovky(int pozicia)

{

int riadok, znak;

for (riadok = 0; riadok < RIADKY; riadok++)

{

for (znak = 0; znak < STLPCE; znak++)

{

if (je_ramcek(riadok, znak))

printf("+");

else if (som_vnutri_kruhu(riadok, znak, pozicia))

printf("*");

else

printf(" ");

}

printf("\n");

}

int main()

{

int pos = 10;

while (1 == 1)

{

vypis_obrazovky(pos);

pos += 2*(rand()%2)-1;

PAUSE();

CLEAR_SCREEN();

}

return 0;

}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)
int pocet_dni(int mesiac)
{
	int pocet = 0;
	if (1 == mesiac || 3 == mesiac || 5 == mesiac)
	{
		pocet = 31;
	}
	else if (2 == mesiac)
	{
		pocet = 28;
	}
	else if (4 == mesiac || 6 == mesiac)
	{
		pocet = 30;
	}
	
	return pocet;
}

//pre kazdy mesiac, vypis pocet dni
void vypis_dni()
{
	int mesiac;
	
	//inicializacia pred cyklom
	mesiac = 1;
	
	//CYKLUS s podmienkou
	while (mesiac <= 12)
	{
		//telo cyklu
		printf("Mesiac c. %2d ma %2d dni.\n",
		                mesiac, pocet_dni(mesiac));
		
		//AKTUALIZACIA premennej cyklu
		mesiac++;    //aka: mesiac = mesiac + 1;
	}
	
	//finalizacia za cyklom
}

int main()
{
	vypis_dni();
	return 0;
}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)

int pocet_dni(int mesiac)

{

int pocet = 0;

if (1 == mesiac || 3 == mesiac || 5 == mesiac)

{

pocet = 31;

}

else if (2 == mesiac)

{

pocet = 28;

}

else if (4 == mesiac || 6 == mesiac)

{

pocet = 30;

}

return pocet;

}

//pre kazdy mesiac, vypis pocet dni

void vypis_dni()

{

int mesiac;

//inicializacia pred cyklom

mesiac = 1;

//CYKLUS s podmienkou

while (mesiac <= 12)

{

//telo cyklu

printf("Mesiac c. %2d ma %2d dni.\n",

mesiac, pocet_dni(mesiac));

//AKTUALIZACIA premennej cyklu

mesiac++; //aka: mesiac = mesiac + 1;

}

//finalizacia za cyklom

}

int main()

{

vypis_dni();

return 0;

}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)
int pocet_dni(int mesiac)
{
	int pocet = 0;
	
	switch (mesiac)
	{
		case 2:
			pocet = 28;  // pocet = 28 + jeprestupny(rok)
			break;
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12:
			pocet = 31;
			break;
		default:
			pocet = 30;
			break;
	}
	
	return pocet;
}

//pre kazdy mesiac, vypis pocet dni
void vypis_dni()
{
	int mesiac;
	
	//inicializacia pred cyklom
	mesiac = 1;
	
	//CYKLUS s podmienkou
	while (mesiac <= 12)
	{
		//telo cyklu
		printf("Mesiac c. %2d ma %2d dni.\n",
		                mesiac, pocet_dni(mesiac));
		
		//AKTUALIZACIA premennej cyklu
		mesiac++;    //aka: mesiac = mesiac + 1;
	}
	
	//finalizacia za cyklom
}

int main()
{
	vypis_dni();
	return 0;
}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)

int pocet_dni(int mesiac)

{

int pocet = 0;

switch (mesiac)

{

case 2:

pocet = 28; // pocet = 28 + jeprestupny(rok)

break;

case 1:

case 3:

case 5:

case 7:

case 8:

case 10:

case 12:

pocet = 31;

break;

default:

pocet = 30;

break;

}

return pocet;

}

//pre kazdy mesiac, vypis pocet dni

void vypis_dni()

{

int mesiac;

//inicializacia pred cyklom

mesiac = 1;

//CYKLUS s podmienkou

while (mesiac <= 12)

{

//telo cyklu

printf("Mesiac c. %2d ma %2d dni.\n",

mesiac, pocet_dni(mesiac));

//AKTUALIZACIA premennej cyklu

mesiac++; //aka: mesiac = mesiac + 1;

}

//finalizacia za cyklom

}

int main()

{

vypis_dni();

return 0;

}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)
int pocet_dni(int mesiac)
{
	//TODO:
	return 30;
}

//pre kazdy mesiac, vypis pocet dni
void vypis_dni()
{
	int mesiac;
	//inicializacia pred cyklom
	for (mesiac =  1 ; mesiac <= 12 ; mesiac++)
	{
		//telo cyklu
		printf("Mesiac c. %2d ma %2d dni.\n",
		                mesiac, pocet_dni(mesiac));
	}	
	//finalizacia za cyklom
}

int main()
{
	vypis_dni();
	return 0;
}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)

int pocet_dni(int mesiac)

{

//TODO:

return 30;

}

//pre kazdy mesiac, vypis pocet dni

void vypis_dni()

{

int mesiac;

//inicializacia pred cyklom

for (mesiac = 1 ; mesiac <= 12 ; mesiac++)

{

//telo cyklu

printf("Mesiac c. %2d ma %2d dni.\n",

mesiac, pocet_dni(mesiac));

}

//finalizacia za cyklom

}

int main()

{

vypis_dni();

return 0;

}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)
int pocet_dni(int mesiac)
{
	//TODO:
	return 30;
}

//nacita mesiac a vypise jeho pocet dni, 
// vrati 0, ak zlyhalo nacitanie mesiaca
int vypis_dni()
{
	int mesiac;
	
	//TODO: overit nacitanie?
	do
	{
		printf("Zadaj cislo mesiaca: ");
		scanf("%d", &mesiac);
		
		if (mesiac < 1 || mesiac > 12)
			return 0;
			
		printf("Mesiac c. %2d ma %2d dni.\n",
		            mesiac, pocet_dni(mesiac));
	} while (1 == 1);
	
	return 1;	
}

int main()
{
	//prazdny cyklus?
	vypis_dni();
		
	return 0;
}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)

int pocet_dni(int mesiac)

{

//TODO:

return 30;

}

//nacita mesiac a vypise jeho pocet dni,

// vrati 0, ak zlyhalo nacitanie mesiaca

int vypis_dni()

{

int mesiac;

//TODO: overit nacitanie?

{

printf("Zadaj cislo mesiaca: ");

scanf("%d", &mesiac);

if (mesiac < 1 || mesiac > 12)

return 0;

printf("Mesiac c. %2d ma %2d dni.\n",

mesiac, pocet_dni(mesiac));

} while (1 == 1);

return 1;

}

int main()

{

//prazdny cyklus?

vypis_dni();

return 0;

}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)
int pocet_dni(int mesiac)
{
	return 30 + 
	       ((mesiac + (mesiac > 7)) % 2) 
		   - 2*(mesiac == 2);
}

void znaky(int pocet, char znak, int eol)
{
	int i;
	for (i = pocet; i > 0; i--)
	{
		printf("%c", znak);
	}
	if (eol)
	{
		printf("\n");
	}
}

void hviezdicky(int pocet)
{
	int i;
	for (i = pocet; i > 0; i--)
	{
		printf("*");
	}
	printf("\n");
}

//pre kazdy mesiac, vypis pocet dni
void vypis_dni()
{
	int mesiac, dni;
	
	for (mesiac = 1; mesiac <= 12; mesiac++)
	{
		printf("%2d: ", mesiac);
		
		hviezdicky(pocet_dni(mesiac));

	}
}

void pyramida(int podstava)
{
	int pocet;
	
	for (pocet = 1; pocet <= podstava; pocet+=2)
	{
		znaky((podstava-pocet)/2, ' ', 0);
		znaky(pocet, 'o', 1);
	}	
}

void trojuholnik(int podstava)
{
	int pocet;
	
	for (pocet = 1; pocet <= podstava; pocet++)
	{
		hviezdicky(pocet);
	}	
}

int main()
{
	int i;
	for (i = 0; i < 3; i++)
		pyramida(7);
	return 0;
}

#include <stdio.h>

//vrati pocet dni v mesiaci (cislovane od 1)

int pocet_dni(int mesiac)

{

return 30 +

((mesiac + (mesiac > 7)) % 2)

- 2*(mesiac == 2);

}

void znaky(int pocet, char znak, int eol)

{

int i;

for (i = pocet; i > 0; i--)

{

printf("%c", znak);

}

if (eol)

{

printf("\n");

}

void hviezdicky(int pocet)

{

int i;

for (i = pocet; i > 0; i--)

{

printf("*");

}

printf("\n");

}

//pre kazdy mesiac, vypis pocet dni

void vypis_dni()

{

int mesiac, dni;

for (mesiac = 1; mesiac <= 12; mesiac++)

{

printf("%2d: ", mesiac);

hviezdicky(pocet_dni(mesiac));

}

void pyramida(int podstava)

{

int pocet;

for (pocet = 1; pocet <= podstava; pocet+=2)

{

znaky((podstava-pocet)/2, ' ', 0);

znaky(pocet, 'o', 1);

}

void trojuholnik(int podstava)

{

int pocet;

for (pocet = 1; pocet <= podstava; pocet++)

{

hviezdicky(pocet);

}

int main()

{

int i;

for (i = 0; i < 3; i++)

pyramida(7);

return 0;

}

Použitie polí

Polia predstavujú postupnosť za sebou v pamäti uložených údajov sprístupniteľných cez index.

//deklaracia pola, nedefinovany obsah, maximum KAPACITA prvkov
TYP NAZOV[KAPACITA];   

//deklaracia pola s vymenovanim prvkov, KAPACITA sa moze, ale nemusi vynechat
int prvocisla[] = {2,3,5,7,11,13,17};

//spristupnenie prvku - operator indexovania - indexy od nuly po KAPACITA-1
a = pole[0];  //precita sa prvy prvok a zapise do premennej a
pole[i] = a;  //obsah premennej a sa zapise do pola na index ulozeny v premennej i

//deklaracia pola, nedefinovany obsah, maximum KAPACITA prvkov

TYP NAZOV[KAPACITA];

//deklaracia pola s vymenovanim prvkov, KAPACITA sa moze, ale nemusi vynechat

int prvocisla[] = {2,3,5,7,11,13,17};

//spristupnenie prvku - operator indexovania - indexy od nuly po KAPACITA-1

a = pole[0]; //precita sa prvy prvok a zapise do premennej a

pole[i] = a; //obsah premennej a sa zapise do pola na index ulozeny v premennej i

Viac detailov k inicializácii: http://en.cppreference.com/w/c/language/array_initialization

Viacrozmerné polia

Štandardne polia, ktorých prvkami sú iné polia.

//pole troch poli, z ktorych kazde ma 5 prvkov typu int
int pole2D[3][5];   

//pole NS stranok po NR riadkoch po NC+1 znakoch kazdy riadok
char kniha[NS][NR][NC+1];

//pole troch poli, z ktorych kazde ma 5 prvkov typu int

int pole2D[3][5];

//pole NS stranok po NR riadkoch po NC+1 znakoch kazdy riadok

char kniha[NS][NR][NC+1];

Funkcia na výpis obsahu poľa

#include <stdio.h>

//funkcia vypise obsah pola, verzia pre int polia
void vypis_pole(const int pole[], int n)
{
    int i;
    printf("Velkost pola: %i\n", n);
    for (i = 0; i < n; i++)
    {
        printf("%lf ", pole[i]);
    }
    printf("\n");
}

//priklady pouzitia 
int main()
{
    int pole[] = {1,2,3,4,5};
    int n = sizeof(pole)/sizeof(pole[0]); //iba tam, kde je pole deklarovane

    //vypise cele pole
    vypis_pole(pole, n);

    //vypise prve 3 prvky
    vypis_pole(pole, 3);

    //vypise posledne 2 prvky
    vypis_pole(pole+n-2, 2);

    return 0;
}

#include <stdio.h>

//funkcia vypise obsah pola, verzia pre int polia

void vypis_pole(const int pole[], int n)

{

int i;

printf("Velkost pola: %i\n", n);

for (i = 0; i < n; i++)

{

printf("%lf ", pole[i]);

}

printf("\n");

}

//priklady pouzitia

int main()

{

int pole[] = {1,2,3,4,5};

int n = sizeof(pole)/sizeof(pole[0]); //iba tam, kde je pole deklarovane

//vypise cele pole

vypis_pole(pole, n);

//vypise prve 3 prvky

vypis_pole(pole, 3);

//vypise posledne 2 prvky

vypis_pole(pole+n-2, 2);

return 0;

}

Funkcia na načítanie údajov do poľa

#include <stdio.h>
#define MAXPOLE 100

//vstupom je adresa pola, kam sa nacitava (verzia pre double)
// a adresa premennej, kde sa uchovava velkost pola: 
//   * pred funkciou musi byt maximum, co sa da ulozit
//   * po funkcii bude mat pocet aktualne ulozenych udajov
void nacitaj_pole(double pole[], int *pN)
{
    int i, n;
    do
    {
       printf("Zadaj kolko prvkov\n");
       scanf("%i", &n);
    } while (n > *pN);    //kontrola pretecenia

    // nacitanie obsahu
    for (i = 0; i < n; i++)
    {
        scanf("%lf", &pole[i]);
    }
    //ulozenie novej dlzky pola
    *pN = n;
}

//priklad pouzitia
int main()
{
    double field[MAXPOLE];
    int n = sizeof(field)/sizeof(field[0]);
 
    nacitaj_pole(field, &n);
    vypis_pole(field, n);

    return 0;
}

#include <stdio.h>

#define MAXPOLE 100

//vstupom je adresa pola, kam sa nacitava (verzia pre double)

// a adresa premennej, kde sa uchovava velkost pola:

// * pred funkciou musi byt maximum, co sa da ulozit

// * po funkcii bude mat pocet aktualne ulozenych udajov

void nacitaj_pole(double pole[], int *pN)

{

int i, n;

{

printf("Zadaj kolko prvkov\n");

scanf("%i", &n);

} while (n > *pN); //kontrola pretecenia

// nacitanie obsahu

for (i = 0; i < n; i++)

{

scanf("%lf", &pole[i]);

}

//ulozenie novej dlzky pola

*pN = n;

}

//priklad pouzitia

int main()

{

double field[MAXPOLE];

int n = sizeof(field)/sizeof(field[0]);

nacitaj_pole(field, &n);

vypis_pole(field, n);

return 0;

}

Funkcia na kopírovanie obsahu poľa

#include <stdio.h>
#include <memory.h>
#define MAXPOLE 100

//vstupom su adresy poli, a pocet poloziek, ktore sa kopiruju
//  POZOR na mozne pretecenie
void kopiruj(int ciel[], int zdroj[], int n)
{
    int i;
    for (i = 0; i < n; i++)
    {
        ciel[i] = zdroj[i];
    }
}

//priklad pouzitia
int main()
{
    int pole1[MAXPOLE], pole2[MAXPOLE];
    int n1 = sizeof(pole1)/sizeof(pole1[0]);
    int n2;
 
    nacitaj_pole(pole1, &n1);
    
    n2 = n1;
    kopiruj(pole2, pole1, n2);
    
    //to iste cez kniznicnu funkciu:
    memcpy(pole2, pole1, n2*sizeof(pole1[0]));

    vypis_pole(pole2, n2);
 
    return 0;
}

#include <stdio.h>

#include <memory.h>

#define MAXPOLE 100

//vstupom su adresy poli, a pocet poloziek, ktore sa kopiruju

// POZOR na mozne pretecenie

void kopiruj(int ciel[], int zdroj[], int n)

{

int i;

for (i = 0; i < n; i++)

{

ciel[i] = zdroj[i];

}

//priklad pouzitia

int main()

{

int pole1[MAXPOLE], pole2[MAXPOLE];

int n1 = sizeof(pole1)/sizeof(pole1[0]);

int n2;

nacitaj_pole(pole1, &n1);

n2 = n1;

kopiruj(pole2, pole1, n2);

//to iste cez kniznicnu funkciu:

memcpy(pole2, pole1, n2*sizeof(pole1[0]));

vypis_pole(pole2, n2);

return 0;

}

Funkcia na porovnanie obsahu polí

#include <stdio.h>
#include <memory.h>
#define MAXPOLE 100

//vstupom su adresy poli, a pocet poloziek, ktore sa porovnavaju
// vracia iba 0/1 (zhoda/nezhoda)
int porovnaj(int pole1[], int pole2[], int n)
{
    int i;
    for (i = 0; i < n; i++)
    {
        if (pole1[i] != pole2[i])
            return 0;
    }
    return 1;
}
//priklad pouzitia
int main()
{
    int pole1[MAXPOLE], pole2[MAXPOLE];
    int n1 = sizeof(pole1)/sizeof(pole1[0]);
    int n2 = sizeof(pole2)/sizeof(pole2[0]);
    int minn;
 
    nacitaj_pole(pole1, &n1);
    nacitaj_pole(pole2, &n2);
    
    minn = n1 < n2 ? n1 : n2;
    if (porovnaj(pole1, pole2, minn))
       printf("Zhodny obsah\n");    

    //to iste cez kniznicnu funkciu:
    if (memcmp(pole1, pole2, minn*sizeof(pole1[0])) == 0)   //vracia 0 iba v pripade zhody
       printf("Zhodny obsah\n");        
 
    return 0;
}

#include <stdio.h>

#include <memory.h>

#define MAXPOLE 100

//vstupom su adresy poli, a pocet poloziek, ktore sa porovnavaju

// vracia iba 0/1 (zhoda/nezhoda)

int porovnaj(int pole1[], int pole2[], int n)

{

int i;

for (i = 0; i < n; i++)

{

if (pole1[i] != pole2[i])

return 0;

}

return 1;

}

//priklad pouzitia

int main()

{

int pole1[MAXPOLE], pole2[MAXPOLE];

int n1 = sizeof(pole1)/sizeof(pole1[0]);

int n2 = sizeof(pole2)/sizeof(pole2[0]);

int minn;

nacitaj_pole(pole1, &n1);

nacitaj_pole(pole2, &n2);

minn = n1 < n2 ? n1 : n2;

if (porovnaj(pole1, pole2, minn))

printf("Zhodny obsah\n");

//to iste cez kniznicnu funkciu:

if (memcmp(pole1, pole2, minn*sizeof(pole1[0])) == 0) //vracia 0 iba v pripade zhody

printf("Zhodny obsah\n");

return 0;

}

Funkcia na vymazanie údajov z poľa

#include <stdio.h>
#define MAXPOLE 100

//ulohou funkcie je vymazat z pola vsetky vyskyty prvku x
//  pN je smernik na premennu, ktora drzi velkost pola (pred aj po vymazani)
//  vrati pocet vymazanych
int vymaz_vsetky(double pole[], int *pN, double x)
{
    int i, j, pocet = 0;
    for (i = 0; i < *pN; i++)
    {
        if (pole[i] == x)
        { 
            //pomaly variant s dvojitym cyklom
            for (j = i+1; j < *pN; j++)
            {
                //zoberiem hodnotu z j-tej pozicie a skopirujem ju na predoslu (j-1) poziciu
                //  v dalsom kroku cyklu sa to prepise nasledovnou hodnotou
                pole[j-1] = pole[j];
            }
            //zmenime pocet a skorigujeme index (lebo sme sa posunuli o jedna dozadu)
            *pN = *pN - 1;
            i--;
        }
    }
    return pocet;
}
int main()
{
    double field[MAXPOLE];
    int n;
    int total = sizeof(field)/sizeof(field[0]);
    
    n = total;
    nacitaj_pole(field, &n);
    
    vypis_pole(field, n);
    
    //vymaze vsetky vyskyty prveho prvku
    vymaz_vsetky(field, &n, field[0]);

    vypis_pole(field, n);

    return 0;
}

#include <stdio.h>

#define MAXPOLE 100

//ulohou funkcie je vymazat z pola vsetky vyskyty prvku x

// pN je smernik na premennu, ktora drzi velkost pola (pred aj po vymazani)

// vrati pocet vymazanych

int vymaz_vsetky(double pole[], int *pN, double x)

{

int i, j, pocet = 0;

for (i = 0; i < *pN; i++)

{

if (pole[i] == x)

{

//pomaly variant s dvojitym cyklom

for (j = i+1; j < *pN; j++)

{

//zoberiem hodnotu z j-tej pozicie a skopirujem ju na predoslu (j-1) poziciu

// v dalsom kroku cyklu sa to prepise nasledovnou hodnotou

pole[j-1] = pole[j];

}

//zmenime pocet a skorigujeme index (lebo sme sa posunuli o jedna dozadu)

*pN = *pN - 1;

i--;

}

return pocet;

}

int main()

{

double field[MAXPOLE];

int n;

int total = sizeof(field)/sizeof(field[0]);

n = total;

nacitaj_pole(field, &n);

vypis_pole(field, n);

//vymaze vsetky vyskyty prveho prvku

vymaz_vsetky(field, &n, field[0]);

vypis_pole(field, n);

return 0;

}

Príklady na polia

#include <stdio.h>

//vyuzijeme pole:
//PRE: 1 <= m && m <= 12
char* nazov_mesiaca(int m)
{
	char* mena[] = {"januar","februar","marec","april","maj","jun",
	                "jul","august","september","oktober","november","december"};
	
	return mena[m-1];
}


//vyuzijeme pole:
//PRE: 1 <= m && m <= 12
int pocet_dni(int m)
{	
	int pocty[] = {31,28,31,30,31,30,31,31,30,31,30,31};
	
	return pocty[m-1];
}

//TODO: 
// lokalne, globalne pole, staticke pole
// pole zadanej dlzky, pole premennej dlzky

int main()
{
	int mesiac;
	
	for (mesiac = 1; mesiac <= 12; mesiac++)	
	{
		printf("Mesiac %-9s ma %2d dni.\n", 
				nazov_mesiaca(mesiac), pocet_dni(mesiac));	
	}	
			
	return 0;
}

#include <stdio.h>

//vyuzijeme pole:

//PRE: 1 <= m && m <= 12

char* nazov_mesiaca(int m)

{

char* mena[] = {"januar","februar","marec","april","maj","jun",

"jul","august","september","oktober","november","december"};

return mena[m-1];

}

//vyuzijeme pole:

//PRE: 1 <= m && m <= 12

int pocet_dni(int m)

{

int pocty[] = {31,28,31,30,31,30,31,31,30,31,30,31};

return pocty[m-1];

}

//TODO:

// lokalne, globalne pole, staticke pole

// pole zadanej dlzky, pole premennej dlzky

int main()

{

int mesiac;

for (mesiac = 1; mesiac <= 12; mesiac++)

{

printf("Mesiac %-9s ma %2d dni.\n",

nazov_mesiaca(mesiac), pocet_dni(mesiac));

}

return 0;

}

#define MAXDLZKA  70

int main()
{
	int pole[MAXDLZKA];  //deklaracia prazdneho pola
	int i;
	int dlzka;
	
	//priklad: naplnenie pola
	for (i = 0; i < MAXDLZKA; i++)
	{
		scanf("%d", &pole[i]);
		if (pole[i] == 0)
			break;
	}
	dlzka = i;
	//priklad: vypis pola
	//TODO: pouzite MAXDLZKA namiesto dlzka
	for (i = 0; i < dlzka; i++)
	{
		printf("%i\n", pole[i]);
	}
	
	return 0;
}

#define MAXDLZKA 70

int main()

{

int pole[MAXDLZKA]; //deklaracia prazdneho pola

int i;

int dlzka;

//priklad: naplnenie pola

for (i = 0; i < MAXDLZKA; i++)

{

scanf("%d", &pole[i]);

if (pole[i] == 0)

break;

}

dlzka = i;

//priklad: vypis pola

//TODO: pouzite MAXDLZKA namiesto dlzka

for (i = 0; i < dlzka; i++)

{

printf("%i\n", pole[i]);

}

return 0;

}

#define MAX 500

//priklad globalneho pola
int pole[MAX];

//funkcia na vypis pola, vypise z neho "dlzka" prvkov
void print_pole(int p[], int dlzka)
{
	int i;
	for (i = 0; i < dlzka; i++)
		printf("%i\n", p[i]);
}
//funkcia naplni pole postupnostou cisel 
void napln(int p[], int dlzka)
{
	int i;
	for (i = 0; i < dlzka; i++)
		p[i] = i+1;
}

int main()
{
	int pole2[] = {2,3,5,7,11,13,17,19};
	int dlzka = 5;
	
	//pouzitie funkcie s lokalnym polom
	//pozn.: nastava pretecenie, 
	//  v poli je realne menej ako 10 prvkov
	//  ale funkcia to nema ako zistit 
	print_pole(pole, 10);
	
	printf("-------------------\n");
	
	//pouzitie s globalnym polom
	napln(pole,dlzka);
	print_pole(pole, dlzka);
	
	
	return 0;
}

#define MAX 500

//priklad globalneho pola

int pole[MAX];

//funkcia na vypis pola, vypise z neho "dlzka" prvkov

void print_pole(int p[], int dlzka)

{

int i;

for (i = 0; i < dlzka; i++)

printf("%i\n", p[i]);

}

//funkcia naplni pole postupnostou cisel

void napln(int p[], int dlzka)

{

int i;

for (i = 0; i < dlzka; i++)

p[i] = i+1;

}

int main()

{

int pole2[] = {2,3,5,7,11,13,17,19};

int dlzka = 5;

//pouzitie funkcie s lokalnym polom

//pozn.: nastava pretecenie,

// v poli je realne menej ako 10 prvkov

// ale funkcia to nema ako zistit

print_pole(pole, 10);

printf("-------------------\n");

//pouzitie s globalnym polom

napln(pole,dlzka);

print_pole(pole, dlzka);

return 0;

}

#include <stdio.h>
#include <time.h>

#define MAXN   10000000

int isprime(int n)
{
	int i;
	for (i = 2; i < n; i++)
		if (n % i == 0)
			return 0;
	return n > 1;
}

int primes(int pole[], int n)
{
	int x, prvyvolny;
	prvyvolny = 0;
	for (x = 2; x < n; x++)
	{
		if (isprime(x))
		{
			pole[prvyvolny] = x;
			prvyvolny++;
		}
	}
	return prvyvolny;
}

int sieve(int pole[], int n)
{
	int i, j;
	//init
	pole[0] = 0;
	pole[1] = 0;
	for (i = 2; i < n; i++)
	{
		pole[i] = i;
	}
	//sieve
	for (j = 2; j < n; j++)
	{
		if (pole[j] == 0)
			continue;
		
		for (i = j + j; i < n; i += j)
			pole[i] = 0;
	}
	//collect
	j = 0;
	for (i = 0; i < n; i++)
	{
		if (pole[i] != 0)
		{
			pole[j] = pole[i];
			j++;
		}
	}
	return j;	
}

int pole[MAXN];

int main1()
{
	int count;
	clock_t start, end;
	start = clock();
	count = sieve(pole, MAXN);
	end = clock();
	//print_pole(pole, count);
	printf("Delta t=%lf s\n", (end-start)/(double)CLOCKS_PER_SEC);
	return 0;
}

void export(int pole[], int n)
{
	int i;
	printf("const int NPRIMES = %i;\n\n",n);
	printf("int g_primes[] = {\n");
	for (i = 0; i < n; i++)
		printf("%i,\n", pole[i]);
	printf("};\n");
}
int main()
{
	int count;
	count = sieve(globalnepole, MAXN);
	export(globalnepole, count);
	return 0;
}

#include <stdio.h>

#include <time.h>

#define MAXN 10000000

int isprime(int n)

{

int i;

for (i = 2; i < n; i++)

if (n % i == 0)

return 0;

return n > 1;

}

int primes(int pole[], int n)

{

int x, prvyvolny;

prvyvolny = 0;

for (x = 2; x < n; x++)

{

if (isprime(x))

{

pole[prvyvolny] = x;

prvyvolny++;

}

return prvyvolny;

}

int sieve(int pole[], int n)

{

int i, j;

//init

pole[0] = 0;

pole[1] = 0;

for (i = 2; i < n; i++)

{

pole[i] = i;

}

//sieve

for (j = 2; j < n; j++)

{

if (pole[j] == 0)

continue;

for (i = j + j; i < n; i += j)

pole[i] = 0;

}

//collect

j = 0;

for (i = 0; i < n; i++)

{

if (pole[i] != 0)

{

pole[j] = pole[i];

j++;

}

return j;

}

int pole[MAXN];

int main1()

{

int count;

clock_t start, end;

start = clock();

count = sieve(pole, MAXN);

end = clock();

//print_pole(pole, count);

printf("Delta t=%lf s\n", (end-start)/(double)CLOCKS_PER_SEC);

return 0;

}

void export(int pole[], int n)

{

int i;

printf("const int NPRIMES = %i;\n\n",n);

printf("int g_primes[] = {\n");

for (i = 0; i < n; i++)

printf("%i,\n", pole[i]);

printf("};\n");

}

int main()

{

int count;

count = sieve(globalnepole, MAXN);

export(globalnepole, count);

return 0;

}

def isprime(n):
  if n < 2:
    return False
  for x in range(2,n-1):
    if n % x == 0:
      return False
  return True

def primes(n):
  return [x for x in range(n) if isprime(x)]

def primes_e(n):
  lst = list(range(n))
  lst[1] = 0
  for i in range(n):
    x = lst[i]
    if x != 0:
      for j in range(i+x, n, x):
        lst[j] = 0
  return [x for x in lst if x != 0]	

import time

start = time.time()
l1 = primes(30000)
end = time.time()
print(end - start)

start = time.time()
l2 = primes_e(3000000)
end = time.time()
print(end - start)

print(set(l2)==set(l1))

def isprime(n):

if n < 2:

return False

for x in range(2,n-1):

if n % x == 0:

return False

return True

def primes(n):

return [x for x in range(n) if isprime(x)]

def primes_e(n):

lst = list(range(n))

lst[1] = 0

for i in range(n):

x = lst[i]

if x != 0:

for j in range(i+x, n, x):

lst[j] = 0

return [x for x in lst if x != 0]

import time

start = time.time()

l1 = primes(30000)

end = time.time()

print(end - start)

start = time.time()

l2 = primes_e(3000000)

end = time.time()

print(end - start)

print(set(l2)==set(l1))

Príklad swap

#include <stdio.h>

void swap(int *px, int *py)
{
	int tmp;
	
	printf("swap: x = %i, y=%i\n"  ,px , py);
	
	tmp = *px;
	*px = *py;
	*py = tmp;
	
	printf("swap: x = %i, y=%i\n"  ,px , py);
}

void getnewpos(double*px, double *py, double v, int angle)
{
	*px = *px + v * angle;
	if (py != NULL)
	{
		*py = *py - v * angle;
	}
}

int main()
{
	int x = 5, y = 3;
	double a = 0,b = 0;
	
	getnewpos(&a, NULL, 55.4, 34);
	
	printf("main: x = %i, y=%i\n"  ,x , y);
	
	swap(&x, &y);
	
	printf("main: x = %i, y=%i\n"  ,x , y);
	
	return 0;
}

#include <stdio.h>

void swap(int *px, int *py)

{

int tmp;

printf("swap: x = %i, y=%i\n" ,px , py);

tmp = *px;

*px = *py;

*py = tmp;

printf("swap: x = %i, y=%i\n" ,px , py);

}

void getnewpos(double*px, double *py, double v, int angle)

{

*px = *px + v * angle;

if (py != NULL)

{

*py = *py - v * angle;

}

int main()

{

int x = 5, y = 3;

double a = 0,b = 0;

getnewpos(&a, NULL, 55.4, 34);

printf("main: x = %i, y=%i\n" ,x , y);

swap(&x, &y);

printf("main: x = %i, y=%i\n" ,x , y);

return 0;

}

#include <stdio.h>
#include <string.h>


//funkcia najde prvy vyskyt prvku v poli (pole int-ov, smerniky)
int* find_first_int(int *pole, int n, int x) //int*  : funkcia vracia adresu
{
	int i;
	for (i = 0; i < n; i++)
	{
		if (pole[i] == x)
		{
			return &pole[i];  //adresa najdeneho prvku
		}
	}
	
	return NULL;  //specialna adresa (neplatna)
}

//funkcia najde prvy vyskyt prvku v poli (pole int-ov, polia, bez smernikov)
int find_first_index(int pole[], int n, int x)
{
	int i;
	for (i = 0; i < n; i++)
	{
		if (pole[i] == x)
		{
			return i;   //index prvku x
		}
	}
	
	return -1;  //specialny neplatny index
}


//funkcia najde prvy vyskyt prvku v poli (vseobecne, so smernikom na fn)
void* find_first(void *pole, int size_pole,   //kde sa hlada 
                 void *x, int size_x,         //co sa hlada
                 int (*compare)(void*, void*, int) )  //ako sa porovnava
{
	char *ptr, *end;   //ptr: pozicia aktualna, end: za koncom pola
	end = pole + size_pole;
    //preco char* ?  -> aby som sa pohyboval po jednotlivych bajtoch pamate

	// aktualna pozicia sa hybe o size_x, kym neprekroci hranice
	for (ptr = (char*)pole; ptr + size_x <= end; ptr += size_x)
	{
		//volame poskytnutu funkciu na porovnanie
		if (compare(ptr, x, size_x) == 0)
			return ptr;		
	}
	
	return NULL;
}

//porovname obsah pamate ako int-y
int cmp_int(void* a, void* b, int size)
{
	return *((int*) a)   -   *((int*) b);    
}

//porovname obsah pamate ako dva int-y
int cmp_ints(void* a, void* b, int size)
{
	int a1 = ((int*)a)[0], a2 = ((int*)a)[1];  //pretypujeme smernik, pouzijeme ako pole    
	int b1 = ((int*)b)[0], b2 = ((int*)b)[1];    
	int d1 = a1 - b1, d2 = a2 - b2;
	if (d1 != 0)
		return d1;
	return d2;
}


int main1()
{
	int pole[] = {1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,6,7,8};
	int p, odkial, n;
	int x = 3;
	
	odkial = 0;
	n = sizeof(pole)/sizeof(pole[0]);
	p = 0;
	while (p != -1)
	{
		//p = find_first(odkial, koniec-odkial, 3);
		p = find_first_index(pole + odkial, n-odkial, 3 );
		//p je index od zaciatku pola vo funkcii find_first_index
		// realny index je vypocitany: pole[odkial+p] == (pole+odkial)[p] == *(pole+odkial+p)
		
		if (p != -1)
		{
			printf("index: %i\n", p);
			printf("pole[%i] = %i\n", p, pole[p]);
			printf("pole[%i+%i] = %i\n", odkial, p, (pole+odkial)[p]);
		}
		odkial = odkial+p+1;
	}
	
	return 0;
}


int main2()
{
	int pole[] = {1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,6,7,8};
	int* p;
	int* odkial;
	int* koniec;
	int x = 3;
	
	odkial = pole;
	koniec = pole + sizeof(pole)/sizeof(pole[0]);
	p = pole;
	while (p != NULL)
	{
		p = find_first_int(odkial, koniec-odkial, 3);
		
		printf("p=%p\n", p);
		if (p != NULL)
		{
			printf("*p = %i\n", *p);
			printf("index: %i\n", p - pole);
		}
		odkial = p+1;
	}
	
	return 0;
}


int main3()
{
	int pole[] = {1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,6,7,8};
	int* p;
	int* odkial;
	int* koniec;
	int x[] = {3,4};
	
	odkial = pole;
	koniec = pole + sizeof(pole)/sizeof(pole[0]);
	p = pole;
	while (p != NULL)
	{
		p = find_first(odkial, (koniec-odkial) * sizeof(pole[0]), 
		                &x, sizeof(x),
		          cmp_ints );  //najdeme podpostupnost dvoch intov

		//p = find_first(odkial, (koniec-odkial) * sizeof(pole[0]), 
		//                &x[0], sizeof(x[0]),
		//          cmp_int );  //najdeme konkretny int
		
		printf("p=%p\n", p);
		if (p != NULL)
		{
			printf("*p = %i\n", *p);
			printf("*(p+1) = %i\n", *(p+1));
			printf("index: %i\n", p - pole);
		}
		odkial = p+1;
	}
	
	return 0;
}

int main()
{
	main1();
	main2();
	main3();
}

//docasne pole variabilnej dlzky
int test(const int p[], int n)
{
	int pole[n];
	//vyuzitie standardnej kniznice na kopirovanie pamate
	memcpy(pole, p, n * sizeof(int));
}

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#include <stdio.h>

#include <string.h>

//funkcia najde prvy vyskyt prvku v poli (pole int-ov, smerniky)

int* find_first_int(int *pole, int n, int x) //int* : funkcia vracia adresu

{

int i;

for (i = 0; i < n; i++)

{

if (pole[i] == x)

{

return &pole[i]; //adresa najdeneho prvku

}

return NULL; //specialna adresa (neplatna)

}

//funkcia najde prvy vyskyt prvku v poli (pole int-ov, polia, bez smernikov)

int find_first_index(int pole[], int n, int x)

{

int i;

for (i = 0; i < n; i++)

{

if (pole[i] == x)

{

return i; //index prvku x

}

return -1; //specialny neplatny index

}

//funkcia najde prvy vyskyt prvku v poli (vseobecne, so smernikom na fn)

void* find_first(void *pole, int size_pole, //kde sa hlada

void *x, int size_x, //co sa hlada

int (*compare)(void*, void*, int) ) //ako sa porovnava

{

char *ptr, *end; //ptr: pozicia aktualna, end: za koncom pola

end = pole + size_pole;

//preco char* ? -> aby som sa pohyboval po jednotlivych bajtoch pamate

// aktualna pozicia sa hybe o size_x, kym neprekroci hranice

for (ptr = (char*)pole; ptr + size_x <= end; ptr += size_x)

{

//volame poskytnutu funkciu na porovnanie

if (compare(ptr, x, size_x) == 0)

return ptr;

}

return NULL;

}

//porovname obsah pamate ako int-y

int cmp_int(void* a, void* b, int size)

{

return *((int*) a) - *((int*) b);

}

//porovname obsah pamate ako dva int-y

int cmp_ints(void* a, void* b, int size)

{

int a1 = ((int*)a)[0], a2 = ((int*)a)[1]; //pretypujeme smernik, pouzijeme ako pole

int b1 = ((int*)b)[0], b2 = ((int*)b)[1];

int d1 = a1 - b1, d2 = a2 - b2;

if (d1 != 0)

return d1;

return d2;

}

int main1()

{

int pole[] = {1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,6,7,8};

int p, odkial, n;

int x = 3;

odkial = 0;

n = sizeof(pole)/sizeof(pole[0]);

p = 0;

while (p != -1)

{

//p = find_first(odkial, koniec-odkial, 3);

p = find_first_index(pole + odkial, n-odkial, 3 );

//p je index od zaciatku pola vo funkcii find_first_index

// realny index je vypocitany: pole[odkial+p] == (pole+odkial)[p] == *(pole+odkial+p)

if (p != -1)

{

printf("index: %i\n", p);

printf("pole[%i] = %i\n", p, pole[p]);

printf("pole[%i+%i] = %i\n", odkial, p, (pole+odkial)[p]);

}

odkial = odkial+p+1;

}

return 0;

}

int main2()

{

int pole[] = {1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,6,7,8};

int* p;

int* odkial;

int* koniec;

int x = 3;

odkial = pole;

koniec = pole + sizeof(pole)/sizeof(pole[0]);

p = pole;

while (p != NULL)

{

p = find_first_int(odkial, koniec-odkial, 3);

printf("p=%p\n", p);

if (p != NULL)

{

printf("*p = %i\n", *p);

printf("index: %i\n", p - pole);

}

odkial = p+1;

}

return 0;

}

int main3()

{

int pole[] = {1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,6,7,8};

int* p;

int* odkial;

int* koniec;

int x[] = {3,4};

odkial = pole;

koniec = pole + sizeof(pole)/sizeof(pole[0]);

p = pole;

while (p != NULL)

{

p = find_first(odkial, (koniec-odkial) * sizeof(pole[0]),

&x, sizeof(x),

cmp_ints ); //najdeme podpostupnost dvoch intov

//p = find_first(odkial, (koniec-odkial) * sizeof(pole[0]),

// &x[0], sizeof(x[0]),

// cmp_int ); //najdeme konkretny int

printf("p=%p\n", p);

if (p != NULL)

{

printf("*p = %i\n", *p);

printf("*(p+1) = %i\n", *(p+1));

printf("index: %i\n", p - pole);

}

odkial = p+1;

}

return 0;

}

int main()

{

main1();

main2();

main3();

}

//docasne pole variabilnej dlzky

int test(const int p[], int n)

{

int pole[n];

//vyuzitie standardnej kniznice na kopirovanie pamate

memcpy(pole, p, n * sizeof(int));

}

Príklad na triedenie poľa štruktúr

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

typedef struct _tag
{
	double lat, lon;
} Location;

typedef double celzius_t;

typedef struct
{
	int id_agent;
	Location location;
	time_t timestamp;
	celzius_t temperature;   // in degree Celsius
} Record;

#define DBSIZE 100
Record DataBase[DBSIZE];

#define NUM_AGENTS 10

Location random_location()
{
	static Location location = {0,0};
	
	location.lat += (rand() / (double)RAND_MAX) * (2) - 1;
	location.lon += (rand() / (double)RAND_MAX) * (2) - 1;
	
	return location;
}

Record random_record()
{
	Record record;
	
	record.id_agent = rand() % NUM_AGENTS;
	record.location = random_location();
	record.temperature = (rand() / (double)RAND_MAX) * (60) - 20;
	record.timestamp = time(0) + rand();
	
	return record;
}

void init(Record db[], int size)
{
	int i;
	for (i = 0; i < size; i++)
		db[i] = random_record();
}

void print_record(Record record)
{
	printf("AGENT%02i:\n", record.id_agent );
	printf(" Loc: %3.6lf, %3.6lf\n", record.location.lat, record.location.lon);
	printf(" Temperature: %2.2lf C\n", record.temperature);
	printf(" Time: %s\n", asctime(gmtime(&record.timestamp)) );
}


void print(Record db[], int size)
{
	int i;
	for (i = 0; i < size; i++)
		print_record(db[i]);
}

void print_indirect(Record* index[], int size)
{
	int i;
	for (i = 0; i < size; i++)
		print_record( *(index[i])  );
}

int cmp_record_by_id(const void *a, const void *b)
{
	Record *r1 = (Record*) a;
	Record *r2 = (Record*) b;
	return r1->id_agent - r2->id_agent;
}

void sort_by_id(Record db[], int size)
{
	qsort(db, size, sizeof(Record), cmp_record_by_id);
}

int cmp_record_by_time(const void *a, const void *b)
{
	Record *r1 = (Record*) a;
	Record *r2 = (Record*) b;
	return difftime(r1->timestamp, r2->timestamp);
}

void sort_by_time(Record db[], int size)
{
	qsort(db, size, sizeof(Record), cmp_record_by_time);
}

int cmp_record_by_time_indirect(const void *a, const void *b)
{
	Record **r1 = (Record**) a;
	Record **r2 = (Record**) b;
	return difftime((*r1)->timestamp, (*r2)->timestamp);
}

void index_by_time(Record db[], int size, Record* index[])
{
	int i;
	for (i = 0; i < size; i++)
		index[i] = &db[i];
	
	qsort(index, size, sizeof(Record*), cmp_record_by_time_indirect);
}

int main()
{
	srand(time(0));
	Record* index_time[DBSIZE];
	
	init(DataBase, DBSIZE);
	
	
//	sort_by_id(DataBase, DBSIZE);
//	print(DataBase, 10);
//	system("pause");

	index_by_time(DataBase, DBSIZE, index_time);
	print(DataBase, 10);
	system("pause");
	print_indirect(index_time, 10);
	
	return 0;
}

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#include <stdio.h>

#include <time.h>

#include <stdlib.h>

typedef struct _tag

{

double lat, lon;

} Location;

typedef double celzius_t;

typedef struct

{

int id_agent;

Location location;

time_t timestamp;

celzius_t temperature; // in degree Celsius

} Record;

#define DBSIZE 100

Record DataBase[DBSIZE];

#define NUM_AGENTS 10

Location random_location()

{

static Location location = {0,0};

location.lat += (rand() / (double)RAND_MAX) * (2) - 1;

location.lon += (rand() / (double)RAND_MAX) * (2) - 1;

return location;

}

Record random_record()

{

Record record;

record.id_agent = rand() % NUM_AGENTS;

record.location = random_location();

record.temperature = (rand() / (double)RAND_MAX) * (60) - 20;

record.timestamp = time(0) + rand();

return record;

}

void init(Record db[], int size)

{

int i;

for (i = 0; i < size; i++)

db[i] = random_record();

}

void print_record(Record record)

{

printf("AGENT%02i:\n", record.id_agent );

printf(" Loc: %3.6lf, %3.6lf\n", record.location.lat, record.location.lon);

printf(" Temperature: %2.2lf C\n", record.temperature);

printf(" Time: %s\n", asctime(gmtime(&record.timestamp)) );

}

void print(Record db[], int size)

{

int i;

for (i = 0; i < size; i++)

print_record(db[i]);

}

void print_indirect(Record* index[], int size)

{

int i;

for (i = 0; i < size; i++)

print_record( *(index[i]) );

}

int cmp_record_by_id(const void *a, const void *b)

{

Record *r1 = (Record*) a;

Record *r2 = (Record*) b;

return r1->id_agent - r2->id_agent;

}

void sort_by_id(Record db[], int size)

{

qsort(db, size, sizeof(Record), cmp_record_by_id);

}

int cmp_record_by_time(const void *a, const void *b)

{

Record *r1 = (Record*) a;

Record *r2 = (Record*) b;

return difftime(r1->timestamp, r2->timestamp);

}

void sort_by_time(Record db[], int size)

{

qsort(db, size, sizeof(Record), cmp_record_by_time);

}

int cmp_record_by_time_indirect(const void *a, const void *b)

{

Record **r1 = (Record**) a;

Record **r2 = (Record**) b;

return difftime((*r1)->timestamp, (*r2)->timestamp);

}

void index_by_time(Record db[], int size, Record* index[])

{

int i;

for (i = 0; i < size; i++)

index[i] = &db[i];

qsort(index, size, sizeof(Record*), cmp_record_by_time_indirect);

}

int main()

{

srand(time(0));

Record* index_time[DBSIZE];

init(DataBase, DBSIZE);

// sort_by_id(DataBase, DBSIZE);

// print(DataBase, 10);

// system("pause");

index_by_time(DataBase, DBSIZE, index_time);

print(DataBase, 10);

system("pause");

print_indirect(index_time, 10);

return 0;

}

Znaky

#include <stdio.h>
#include <ctype.h>

//funkcia po vzore "ctype.h"
int je_samohlaska(int c)
{
	switch (tolower(c))
	{
		case 'a':
		case 'e':
		case 'i':
		case 'o':
		case 'u':
		case 'y':
			return 1;
		default:
			return 0;
	}
	return 0;
}

//funkcia na vypis postupnosti bajtov z pamate, zadana je dlzka
void print_mem(unsigned char * p, int len)
{
	int i;
	for (i = 0; i < len; i++)
		printf("%02x: %c\n", p[i], *(p+i));
}

//ako predosle, ale nie je znama dlzka, iba ukoncenie 0
void print_mem2(unsigned char * p)
{
	while (*p != 0)
	{
		printf("%02x: %c\n", *p, *p);
		p++;
	}
}

int main()
{
	int a, b, c = 0x54534554;
	
	//dve deklaracie toho isteho pola znakov
//	char pole[] = {'t', 'e', 's', 't', '\0'};
	char pole[] = "test";
	//retazec: pole znakov ukoncene 0  (v znakovom zapise '\0')
	
	char *p = pole;
	//a = 'a'; b = 2;
	//c = a+b;
	
	print_mem(&c, sizeof(int));		
	print_mem2(&c);		

	print_mem(pole, sizof(pole));		
	print_mem2(pole);		
	
	return 0;
}

#include <stdio.h>

#include <ctype.h>

//funkcia po vzore "ctype.h"

int je_samohlaska(int c)

{

switch (tolower(c))

{

case 'a':

case 'e':

case 'i':

case 'o':

case 'u':

case 'y':

return 1;

default:

return 0;

}

return 0;

}

//funkcia na vypis postupnosti bajtov z pamate, zadana je dlzka

void print_mem(unsigned char * p, int len)

{

int i;

for (i = 0; i < len; i++)

printf("%02x: %c\n", p[i], *(p+i));

}

//ako predosle, ale nie je znama dlzka, iba ukoncenie 0

void print_mem2(unsigned char * p)

{

while (*p != 0)

{

printf("%02x: %c\n", *p, *p);

p++;

}

int main()

{

int a, b, c = 0x54534554;

//dve deklaracie toho isteho pola znakov

// char pole[] = {'t', 'e', 's', 't', '\0'};

char pole[] = "test";

//retazec: pole znakov ukoncene 0 (v znakovom zapise '\0')

char *p = pole;

//a = 'a'; b = 2;

//c = a+b;

print_mem(&c, sizeof(int));

print_mem2(&c);

print_mem(pole, sizof(pole));

print_mem2(pole);

return 0;

}

Reťazce

#include <stdio.h>

//PRE: minimalne mat miesto na 27 znakov...
void abeceda(char pole[])
{
	int i;
	
	for (i = 0; i < 26; i++)
		pole[i] = 'a'+i;   //naplnime pole abecedou
	pole[26] = '\0';	   // a pridame ukoncovaci znak
}

int main()
{
	//rozne retazce:
	// smernik ukazujuci do pamate skompilovaneho programu
	char *str1 = "abcdefghijklmnopqrstuvwxyz";
	
	//lokalne pole inicializovane znakmi
	char str2[] = "abcdefghijklmnopqrstuvwxyz";
	
	//dalsie lokalne pole
	char pole[100] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxx";

    //aj ked maju rovnaky obsah, tu sa porovnavaju adresy...	
	printf("Zhoda: %i\n", str1==str2);
	//vsimnite si rozne velkosti
	printf("sizeof(str1) = %i\n", sizeof(str1));  //smernik
	printf("sizeof(str2) = %i\n", sizeof(str2));  //pole

	
	//priklad nacitania riadku zo vstupu
	fgets(pole, 100, stdin);

	//priklad nacitania slova zo vstupu
	scanf("%10s", pole);
	
	//priklad naplnenia pola funkciou
	abeceda(pole);
	
	//priklad vypisu retazca: je jedno, ako bol ziskany
	printf("str1 = %s\n", str1);
	printf("str2 = %s\n", str2);
	printf("pole = %s\n", pole);
	
	//v jednom poli moze byt ulozenych viac retazcov...
	printf("pole+27 = %s\n", pole+27);
	
	return 0;
}

#include <stdio.h>

//PRE: minimalne mat miesto na 27 znakov...

void abeceda(char pole[])

{

int i;

for (i = 0; i < 26; i++)

pole[i] = 'a'+i; //naplnime pole abecedou

pole[26] = '\0'; // a pridame ukoncovaci znak

}

int main()

{

//rozne retazce:

// smernik ukazujuci do pamate skompilovaneho programu

char *str1 = "abcdefghijklmnopqrstuvwxyz";

//lokalne pole inicializovane znakmi

char str2[] = "abcdefghijklmnopqrstuvwxyz";

//dalsie lokalne pole

char pole[100] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxx";

//aj ked maju rovnaky obsah, tu sa porovnavaju adresy...

printf("Zhoda: %i\n", str1==str2);

//vsimnite si rozne velkosti

printf("sizeof(str1) = %i\n", sizeof(str1)); //smernik

printf("sizeof(str2) = %i\n", sizeof(str2)); //pole

//priklad nacitania riadku zo vstupu

fgets(pole, 100, stdin);

//priklad nacitania slova zo vstupu

scanf("%10s", pole);

//priklad naplnenia pola funkciou

abeceda(pole);

//priklad vypisu retazca: je jedno, ako bol ziskany

printf("str1 = %s\n", str1);

printf("str2 = %s\n", str2);

printf("pole = %s\n", pole);

//v jednom poli moze byt ulozenych viac retazcov...

printf("pole+27 = %s\n", pole+27);

return 0;

}

Príklady z cvičenia

#include <stdio.h>

//vypis vsetkych argumentov programu:
int main(int argc, char* argv[])
{
	int i;
	for (i = 0; i < argc; i++)
	{
		printf("%i: %s\n", i, argv[i]);
	}

	return 0;
}

#include <stdio.h>

//vypis vsetkych argumentov programu:

int main(int argc, char* argv[])

{

int i;

for (i = 0; i < argc; i++)

{

printf("%i: %s\n", i, argv[i]);

}

return 0;

}

#include <stdio.h>

//priklad: vyuzitie funkcie sprintf/sscanf
int main(int argc, char* argv[])
{
	//6 znakov na extra pismena, 10 znakov na cislo
	int kapacita = 6 + 10 + strlen(argv[1]) + strlen(argv[2]);
	char buffer[kapacita];
	int x;
	
	sprintf(buffer, "%i: %s - %s", kapacita, argv[1], argv[2]);

	printf("Vzniklo: %s\n", buffer);
	
	sscanf(argv[1], "%i", &x);
	printf("2x= %i\n", 2*x);


	return 0;
}

#include <stdio.h>

//priklad: vyuzitie funkcie sprintf/sscanf

int main(int argc, char* argv[])

{

//6 znakov na extra pismena, 10 znakov na cislo

int kapacita = 6 + 10 + strlen(argv[1]) + strlen(argv[2]);

char buffer[kapacita];

int x;

sprintf(buffer, "%i: %s - %s", kapacita, argv[1], argv[2]);

printf("Vzniklo: %s\n", buffer);

sscanf(argv[1], "%i", &x);

printf("2x= %i\n", 2*x);

return 0;

}

#include <stdio.h>

//realizacia porovnania retazcov, case insensitive
int compare(char * s1, char * s2)
{
	while (toupper(*s1) == toupper(*s2) && *s1 != '\0')
	{
		s1++; s2++;
	}
	return toupper(*s1) - toupper(*s2);
}

//testovaci kod
int main(int argc, char* argv[])
{
	//na regularne porovnanie sa da vyuzit strcmp
	if (compare(argv[1], argv[2]) == 0)
	{
		printf("Zhoda\n");
	}
	else
	{
		printf("Nezhoda\n");
	}

	return 0;
}

#include <stdio.h>

//realizacia porovnania retazcov, case insensitive

int compare(char * s1, char * s2)

{

while (toupper(*s1) == toupper(*s2) && *s1 != '\0')

{

s1++; s2++;

}

return toupper(*s1) - toupper(*s2);

}

//testovaci kod

int main(int argc, char* argv[])

{

//na regularne porovnanie sa da vyuzit strcmp

if (compare(argv[1], argv[2]) == 0)

{

printf("Zhoda\n");

}

else

{

printf("Nezhoda\n");

}

return 0;

}

#include <stdio.h>
#include <string.h>

//funkcia, ktora vlozi jeden retazec do druheho
// po vzore strcat
char* insert(char* to, char* what, int where)
{
	if (where < 0)
		where = 0;
	if (where > strlen(to))
		where = strlen(to);
	
	memmove(to+where+strlen(what), to+where, strlen(to)-where+1);
	memmove(to+where, what, strlen(what));
	return to;
}

//testovaci kod
int main(int argc, char* argv[])
{
	char * s1 = argv[1];
	char * s2 = argv[2];
	int ix = atoi (argv[3]);
	//musime mat rezervovanu dostatocnu pamat
	char buffer[strlen(s1)+strlen(s2)+1];
	
	//vyuzijeme strcpy na inicializaciu buffera
	strcpy(buffer, s1);
	insert(buffer, s2, ix);
	printf("%s\n", buffer);

	return 0;
}

#include <stdio.h>

#include <string.h>

//funkcia, ktora vlozi jeden retazec do druheho

// po vzore strcat

char* insert(char* to, char* what, int where)

{

if (where < 0)

where = 0;

if (where > strlen(to))

where = strlen(to);

memmove(to+where+strlen(what), to+where, strlen(to)-where+1);

memmove(to+where, what, strlen(what));

return to;

}

//testovaci kod

int main(int argc, char* argv[])

{

char * s1 = argv[1];

char * s2 = argv[2];

int ix = atoi (argv[3]);

//musime mat rezervovanu dostatocnu pamat

char buffer[strlen(s1)+strlen(s2)+1];

//vyuzijeme strcpy na inicializaciu buffera

strcpy(buffer, s1);

insert(buffer, s2, ix);

printf("%s\n", buffer);

return 0;

}

Príklad na prácu so súbormi

/*
Program archivuje subory

archive.exe ARCHIV [zoznam suborov]
extract.exe ARCHIV

Datovy format:
MENO SUBORU
DLZKA
DATA
MENO SUBORU
DLZKA
DATA
 */

#include <stdio.h>
#define ERR_OPEN -1
#define OK        0

int copy(FILE* out, FILE* in)
{
	int c;
	int count = 0;
	while ( (c = fgetc(in)) != EOF )
	{
		fputc(c, out);
		count++;
	}
	return count;
}

int archive_file(FILE *out, char* filename)
{
	FILE *input;
	int len;
	long pos;
	
	input = fopen(filename, "rb");
	if (input == NULL)
		return ERR_OPEN;
	
	fprintf(out, "%s\n", filename);
	
	pos = ftell(out);
	fwrite(&len, sizeof(len), 1, out);
	
	len = copy(out, input);
	
	fseek(out, pos, SEEK_SET);
	fwrite(&len, sizeof(len), 1, out);
	fseek(out, 0, SEEK_END);
	
	return OK;
}

int archive(const char* archivename, int num, char* list[])
{
	FILE *out;
	int i, ok = OK;
	
	out = fopen(archivename, "wb");
	if (out == NULL)
		return ERR_OPEN;
		
	for (i = 0; i < num; i++)
	{
		if (archive_file(out, list[i]) == ERR_OPEN)
		{
			ok = ERR_OPEN;
			break;
		}
	}
	
	fclose(out);
	return ok;
}

int main(int argc, char* argv[])
{
	if (argc <= 2)
		return -1;
		
	archive(argv[1],argc-2, argv+2);
	
	
	return 0;
}

Program archivuje subory

archive.exe ARCHIV [zoznam suborov]

extract.exe ARCHIV

Datovy format:

MENO SUBORU

DLZKA

DATA

MENO SUBORU

DLZKA

DATA

#include <stdio.h>

#define ERR_OPEN -1

#define OK 0

int copy(FILE* out, FILE* in)

{

int c;

int count = 0;

while ( (c = fgetc(in)) != EOF )

{

fputc(c, out);

count++;

}

return count;

}

int archive_file(FILE *out, char* filename)

{

FILE *input;

int len;

long pos;

input = fopen(filename, "rb");

if (input == NULL)

return ERR_OPEN;

fprintf(out, "%s\n", filename);

pos = ftell(out);

fwrite(&len, sizeof(len), 1, out);

len = copy(out, input);

fseek(out, pos, SEEK_SET);

fwrite(&len, sizeof(len), 1, out);

fseek(out, 0, SEEK_END);

return OK;

}

int archive(const char* archivename, int num, char* list[])

{

FILE *out;

int i, ok = OK;

out = fopen(archivename, "wb");

if (out == NULL)

return ERR_OPEN;

for (i = 0; i < num; i++)

{

if (archive_file(out, list[i]) == ERR_OPEN)

{

ok = ERR_OPEN;

break;

}

fclose(out);

return ok;

}

int main(int argc, char* argv[])

{

if (argc <= 2)

return -1;

archive(argv[1],argc-2, argv+2);

return 0;

}

/*
Program archivuje subory

archive.exe ARCHIV [zoznam suborov]
extract.exe ARCHIV

Datovy format:
MENO SUBORU
DLZKA
DATA
MENO SUBORU
DLZKA
DATA
 */

#include <stdio.h>
#include <string.h>
#define ERR_OPEN -1
#define OK        0

int copy_bytes(FILE* out, FILE* in, int len)
{
	int c;
	while (len > 0)
	{
		c = fgetc(in);
		fputc(c, out);
		len--;
	}

	return len;
}

int extract_file(FILE *in, char* filename, int len)
{
	FILE *output;

	output = fopen(filename, "wb");
	if (output == NULL)
		return ERR_OPEN;
	
	copy_bytes(output, in, len);
	fclose(output);
	return OK;
}
#define MAXFILENAME 10000
int extract(const char* archivename)
{
	FILE *in;
	int i, len, ok = OK;
	static char buffer[MAXFILENAME];
	
	in = fopen(archivename, "rb");
	if (in == NULL)
		return ERR_OPEN;
		
	do {
		if (fgets(buffer, MAXFILENAME, in) == NULL)
			break;
		len = strlen(buffer);
		if (len < 1 || len >= MAXFILENAME )
			break;
		buffer[len-1] = '\0';
		
		fread(&len, sizeof(len), 1, in);
		//TODO: verify fread ok...
		
		extract_file(in, buffer, len);
		//TODO: verify extract OK
	} while (1 == 1);
	
	
	fclose(in);
	return ok;
}

int main(int argc, char* argv[])
{
	if (argc <= 1)
		return -1;
		
	extract(argv[1]);
	
	
	return 0;
}

Program archivuje subory

archive.exe ARCHIV [zoznam suborov]

extract.exe ARCHIV

Datovy format:

MENO SUBORU

DLZKA

DATA

MENO SUBORU

DLZKA

DATA

#include <stdio.h>

#include <string.h>

#define ERR_OPEN -1

#define OK 0

int copy_bytes(FILE* out, FILE* in, int len)

{

int c;

while (len > 0)

{

c = fgetc(in);

fputc(c, out);

len--;

}

return len;

}

int extract_file(FILE *in, char* filename, int len)

{

FILE *output;

output = fopen(filename, "wb");

if (output == NULL)

return ERR_OPEN;

copy_bytes(output, in, len);

fclose(output);

return OK;

}

#define MAXFILENAME 10000

int extract(const char* archivename)

{

FILE *in;

int i, len, ok = OK;

static char buffer[MAXFILENAME];

in = fopen(archivename, "rb");

if (in == NULL)

return ERR_OPEN;

do {

if (fgets(buffer, MAXFILENAME, in) == NULL)

break;

len = strlen(buffer);

if (len < 1 || len >= MAXFILENAME )

break;

buffer[len-1] = '\0';

fread(&len, sizeof(len), 1, in);

//TODO: verify fread ok...

extract_file(in, buffer, len);

//TODO: verify extract OK

} while (1 == 1);

fclose(in);

return ok;

}

int main(int argc, char* argv[])

{

if (argc <= 1)

return -1;

extract(argv[1]);

return 0;

}

Dynamická alokácia

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

//Funkcia obrati retazec (nemeni povodny)
const char* reverse(const char* str)
{
	int i, j, len = strlen(str);
	char *pole;
	
	//dynamicka alokacia je jedina vhodna...
	pole = (char*) malloc( (len+1)*sizeof(char) );
	 
	j = 0;
	for (i = len-1; i >= 0; i--)
	{
		pole[j]  = str[i];
		j++;
	}
	pole[j] = '\0';
	
	return pole;
}


int main(int argc, char *argv[])
{
	int i;
	const char *str = "panama";
	const char *new_str = NULL;
	for (i = 0; i >= 0; i++)
	{
		printf("str%04i: %s\n", i, str);
		new_str = reverse(str);
		
		//v cykle spravne uvolnovat pamat 
		// je "mierne problematicke"
		if (i > 0)
			free(str);
		str = new_str;
	}
	
	return 1;
}

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

//Funkcia obrati retazec (nemeni povodny)

const char* reverse(const char* str)

{

int i, j, len = strlen(str);

char *pole;

//dynamicka alokacia je jedina vhodna...

pole = (char*) malloc( (len+1)*sizeof(char) );

j = 0;

for (i = len-1; i >= 0; i--)

{

pole[j] = str[i];

j++;

}

pole[j] = '\0';

return pole;

}

int main(int argc, char *argv[])

{

int i;

const char *str = "panama";

const char *new_str = NULL;

for (i = 0; i >= 0; i++)

{

printf("str%04i: %s\n", i, str);

new_str = reverse(str);

//v cykle spravne uvolnovat pamat

// je "mierne problematicke"

if (i > 0)

free(str);

str = new_str;

}

return 1;

}

Načítanie riadkov

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

typedef struct {
	int pocet;
	char** pole;
} Riadky;

const char* reverse(const char* str);

#define MAXCOUNT 100000
char* readline(FILE* f) 
{ 
	static char buffer[MAXCOUNT];
	int len;

	fgets(buffer, MAXCOUNT, f);
	//TODO: osetrit pretecenie
	
	len = strlen(buffer);
	if (len > 0 && buffer[len-1] == '\n')
		buffer[len-1] = '\0';
	//else ... nenacital riadok
	
	return buffer;
}
int append(Riadky* pRiadky, char* riadok)
{
	char * line;
	//zvacsit pamat
	pRiadky->pole = 
		(char**) 	realloc(pRiadky->pole, 
	                    (pRiadky->pocet+1)*sizeof(char*));
		
	line = (char*) malloc(strlen(riadok)+1);
	strcpy(line, riadok);

	pRiadky->pole[pRiadky->pocet] = line;
	pRiadky->pocet++;
	
	return 1;
}

int nacitaj(const char* meno, Riadky* pRiadky)
{
	FILE *f;
	char *riadok;
	//otvor subor
	f = fopen(meno, "r");
	if (f == NULL)
		return 0;
		
	append(pRiadky, "=== Zaciatok suboru ===");
	
	//nacitaj zo suboru kazdy riadok
	while (!feof(f))
	{
		riadok = readline(f);
		append(pRiadky, riadok);
	}

	//zatvor subor
	fclose(f);
	return 1;
}

void vypis(char* riadky[], int pocet)
{
	int i;
	for (i = 0; i < pocet; i++)
		printf("%s\n", riadky[i]);
}

void empty(Riadky* pRiadky)
{
	int i;
	for (i = 0; i < pRiadky->pocet; i++)
	{
		free(pRiadky->pole[i]);
	}
	if (pRiadky->pole != NULL)
		free(pRiadky->pole);
	
	pRiadky->pocet = 0;
	pRiadky->pole  = NULL;
}

int main(int argc, char *argv[])
{
	Riadky riadky = {0,NULL};
	if (argc < 2)
		return -1;
		
	nacitaj(argv[1], &riadky);
	
	if (riadky.pocet > 10)
		vypis(riadky.pole, 10);
	
	empty(&riadky);
	
	return 1;
}

100

101

102

103

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

typedef struct {

int pocet;

char** pole;

} Riadky;

const char* reverse(const char* str);

#define MAXCOUNT 100000

char* readline(FILE* f)

{

static char buffer[MAXCOUNT];

int len;

fgets(buffer, MAXCOUNT, f);

//TODO: osetrit pretecenie

len = strlen(buffer);

if (len > 0 && buffer[len-1] == '\n')

buffer[len-1] = '\0';

//else ... nenacital riadok

return buffer;

}

int append(Riadky* pRiadky, char* riadok)

{

char * line;

//zvacsit pamat

pRiadky->pole =

(char**) realloc(pRiadky->pole,

(pRiadky->pocet+1)*sizeof(char*));

line = (char*) malloc(strlen(riadok)+1);

strcpy(line, riadok);

pRiadky->pole[pRiadky->pocet] = line;

pRiadky->pocet++;

return 1;

}

int nacitaj(const char* meno, Riadky* pRiadky)

{

FILE *f;

char *riadok;

//otvor subor

f = fopen(meno, "r");

if (f == NULL)

return 0;

append(pRiadky, "=== Zaciatok suboru ===");

//nacitaj zo suboru kazdy riadok

while (!feof(f))

{

riadok = readline(f);

append(pRiadky, riadok);

}

//zatvor subor

fclose(f);

return 1;

}

void vypis(char* riadky[], int pocet)

{

int i;

for (i = 0; i < pocet; i++)

printf("%s\n", riadky[i]);

}

void empty(Riadky* pRiadky)

{

int i;

for (i = 0; i < pRiadky->pocet; i++)

{

free(pRiadky->pole[i]);

}

if (pRiadky->pole != NULL)

free(pRiadky->pole);

pRiadky->pocet = 0;

pRiadky->pole = NULL;

}

int main(int argc, char *argv[])

{

Riadky riadky = {0,NULL};

if (argc < 2)

return -1;

nacitaj(argv[1], &riadky);

if (riadky.pocet > 10)

vypis(riadky.pole, 10);

empty(&riadky);

return 1;

}

Dynamická alokácia matice

//alokujte maticu m x n
double** alloc_matrix(int m, int n)
{
	double** matrix;
	double* row;
	int r;
	
	matrix = (double**) calloc(m, sizeof(double*));
	
	for (r = 0; r < m; r++)
	{
		matrix[r] = (double*) calloc(n, sizeof(double));
	}
	for (r = 0; r < min(m,n); r++)
	{
		matrix[r][r] = 1.0;
	}
	return matrix;
}


//alokujte maticu m x n: pokrocila verzia s 1 alokaciou
double** alloc_matrix(int m, int n)
{
	double** matrix;
	double* row;
	int r;
	
	matrix = (double**) malloc(m*sizeof(double*)
								+ m*n*sizeof(double)
							);
	row = (double*)  (&matrix[m]);
	for (r = 0; r < m; r++)
	{
		matrix[r] = row;
		row += n;
	}
	for (r = 0; r < min(m,n); r++)
	{
		matrix[r][r] = 1.0;
	}
	return matrix;
}

//alokujte maticu m x n

double** alloc_matrix(int m, int n)

{

double** matrix;

double* row;

int r;

matrix = (double**) calloc(m, sizeof(double*));

for (r = 0; r < m; r++)

{

matrix[r] = (double*) calloc(n, sizeof(double));

}

for (r = 0; r < min(m,n); r++)

{

matrix[r][r] = 1.0;

}

return matrix;

}

//alokujte maticu m x n: pokrocila verzia s 1 alokaciou

double** alloc_matrix(int m, int n)

{

double** matrix;

double* row;

int r;

matrix = (double**) malloc(m*sizeof(double*)

+ m*n*sizeof(double)

);

row = (double*) (&matrix[m]);

for (r = 0; r < m; r++)

{

matrix[r] = row;

row += n;

}

for (r = 0; r < min(m,n); r++)

{

matrix[r][r] = 1.0;

}

return matrix;

}

Huffman kompresia súborov

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

//  POPIS read_file():
//      Funkcia, ktora precita obsah suboru (fname) 
//      do dynamickeho pola znakov 
//      a vrati pointer na jeho zaciatok + dlzku.
//  IN:
//      fname   - retazec obsahujuci nazov suboru
//      pLen    - pointer, kam sa zapise dlzka suboru
//  OUT:
//      unsigned char* - pointer na binarny obsah suboru
//      

unsigned char* read_file(char* fname, size_t *pLen)
{
	FILE * f;
	size_t len,pos;
	unsigned char* out;
	
	f = fopen(fname, "rb"); // otvarame subor v binarnom rezime
	if (f == NULL) // kontrolujeme, ci otvaranie prebehlo OK
		return NULL;

	pos = ftell(f);    // aktualna pozicia
    fseek(f, 0, SEEK_END);    // presunieme sa na koniec suboru
    len = ftell(f); // zistenie aktualnej pozicie v subore
    fseek(f, pos, SEEK_SET);  // vratenie sa na zaciatok suboru

	out = (unsigned char*)malloc(len); // alokujeme pamat pre retazec + 1 ukoncovaci znak
	if(out == NULL){
        fprintf(stderr, "Alokacia pamate zlyhala.\n");
		exit(-1);        
	}

	// nacitanie suboru do retazca
	fread(out, sizeof(unsigned char), len, f);

	fclose(f); // zavrieme subor
	
	//vratime dlzku a nacitane data
	*pLen = len;  
	return out;
}

int compress(unsigned char *data, size_t *pLen);

int write_file(char* fname, unsigned char *data, size_t len)
{
	FILE *f = fopen(fname, "wb");
	
	if (f == NULL)
		return 0;
		
	fwrite(data, sizeof(unsigned char), len, f);
	fclose(f);
	return 1;
}

int main(int argc, char* argv[])
{
	size_t len, ones;
	unsigned char * data;
	char *fname = "test.bmp";
	
	if (argc >= 2)
		fname = argv[1];
	
	data = read_file(fname, &len);
	if (data != NULL)
	{
		compress(data, &len);
		write_file("huff.out", data, len);	
		free(data);
	}
	return 0;	
}

#define NSYM  256

typedef struct _symbol {
	int code;
	int count;
	struct _symbol *parent;
	struct _symbol *zero, *one;
} Symbol;

char* huffcode(Symbol* pSymbol)
{
	static char str[NSYM + 1] = "";
	int i = NSYM-1;
	while (pSymbol->parent != 0)
	{
		if (pSymbol->parent->zero == pSymbol)
			str[i] = '0';
		else
			str[i] = '1';
		i--;
		pSymbol = pSymbol->parent;
	}
	return &str[i+1];
}

//PRE: symbols len is 2n
int	huffman(Symbol symbols[], int n)
{
	int i, from = 0, to = n;
	Symbol* tmp;
	Symbol* ptrs[2*n];
	
	for (i = 0; i < 2*n; i++)
		ptrs[i] = &symbols[i];
	
	while (to - from > 1)
	{
		//prve dve su minimum
		for (i = from+1; i < to; i++)
		{
			if (ptrs[i]->count < ptrs[from]->count)
			{
				tmp        = ptrs[from];
				ptrs[from] = ptrs[i];
				ptrs[i] = tmp;
			}
			if (ptrs[i]->count < ptrs[from+1]->count)
			{
				tmp        = ptrs[from+1];
				ptrs[from+1] = ptrs[i];
				ptrs[i] = tmp;
			}
		}
		
		//pridaj na koniec novy uzol...
		ptrs[to]->code  = -1;
		ptrs[to]->count = ptrs[from]->count + 
						    ptrs[from+1]->count;
		ptrs[to]->zero  = ptrs[from];
		ptrs[to]->one  = ptrs[from+1];
		ptrs[from]->parent = ptrs[to];
		ptrs[from+1]->parent = ptrs[to];
		
		to++;
		from += 2;
	}
}

int compress(unsigned char *data, size_t *pLen)
{
	Symbol symbols[2*NSYM] = {0};
	Symbol* pRoot;
	unsigned char *tmp;
	char *code;
	int i, j, len = *pLen;

	for (i = 0; i < NSYM; i++)
		symbols[i].code = i;
	
	for (i = 0; i < len; i++)
		symbols[data[i]].count++;
		
	//debug...
	for (i = 0; i < NSYM; i++)
		printf("%i: %i\n", 
			symbols[i].code,
			symbols[i].count);

	//Huffman, jednoducha verzia...
	huffman(symbols, NSYM);
	
	//debug...	
	for (i = 0; i < NSYM; i++)
	{
		printf("%i: %s\n", symbols[i].code, huffcode(&symbols[i]));
	}
	
	tmp = (unsigned char*) calloc(len, sizeof(unsigned char));
	int bitpos = 0;
	for (i = 0; i < len; i++)
	{
		code = huffcode(&symbols[data[i]]);
		for (j = 0; j < strlen(code); j++)
		{
			tmp[bitpos>>3] ^= (code[j] - '0')<<(bitpos&0x7);
			bitpos++;
		}
	}
	len = (bitpos+7)>>3;
	memcpy(data, tmp, len);
	free(tmp);
	
	*pLen = len;
	return len;
}

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#include <string.h>

#include <stdio.h>

#include <stdlib.h>

// POPIS read_file():

// Funkcia, ktora precita obsah suboru (fname)

// do dynamickeho pola znakov

// a vrati pointer na jeho zaciatok + dlzku.

// IN:

// fname - retazec obsahujuci nazov suboru

// pLen - pointer, kam sa zapise dlzka suboru

// OUT:

// unsigned char* - pointer na binarny obsah suboru

unsigned char* read_file(char* fname, size_t *pLen)

{

FILE * f;

size_t len,pos;

unsigned char* out;

f = fopen(fname, "rb"); // otvarame subor v binarnom rezime

if (f == NULL) // kontrolujeme, ci otvaranie prebehlo OK

return NULL;

pos = ftell(f); // aktualna pozicia

fseek(f, 0, SEEK_END); // presunieme sa na koniec suboru

len = ftell(f); // zistenie aktualnej pozicie v subore

fseek(f, pos, SEEK_SET); // vratenie sa na zaciatok suboru

out = (unsigned char*)malloc(len); // alokujeme pamat pre retazec + 1 ukoncovaci znak

if(out == NULL){

fprintf(stderr, "Alokacia pamate zlyhala.\n");

exit(-1);

}

// nacitanie suboru do retazca

fread(out, sizeof(unsigned char), len, f);

fclose(f); // zavrieme subor

//vratime dlzku a nacitane data

*pLen = len;

return out;

}

int compress(unsigned char *data, size_t *pLen);

int write_file(char* fname, unsigned char *data, size_t len)

{

FILE *f = fopen(fname, "wb");

if (f == NULL)

return 0;

fwrite(data, sizeof(unsigned char), len, f);

fclose(f);

return 1;

}

int main(int argc, char* argv[])

{

size_t len, ones;

unsigned char * data;

char *fname = "test.bmp";

if (argc >= 2)

fname = argv[1];

data = read_file(fname, &len);

if (data != NULL)

{

compress(data, &len);

write_file("huff.out", data, len);

free(data);

}

return 0;

}

#define NSYM 256

typedef struct _symbol {

int code;

int count;

struct _symbol *parent;

struct _symbol *zero, *one;

} Symbol;

char* huffcode(Symbol* pSymbol)

{

static char str[NSYM + 1] = "";

int i = NSYM-1;

while (pSymbol->parent != 0)

{

if (pSymbol->parent->zero == pSymbol)

str[i] = '0';

else

str[i] = '1';

i--;

pSymbol = pSymbol->parent;

}

return &str[i+1];

}

//PRE: symbols len is 2n

int huffman(Symbol symbols[], int n)

{

int i, from = 0, to = n;

Symbol* tmp;

Symbol* ptrs[2*n];

for (i = 0; i < 2*n; i++)

ptrs[i] = &symbols[i];

while (to - from > 1)

{

//prve dve su minimum

for (i = from+1; i < to; i++)

{

if (ptrs[i]->count < ptrs[from]->count)

{

tmp = ptrs[from];

ptrs[from] = ptrs[i];

ptrs[i] = tmp;

}

if (ptrs[i]->count < ptrs[from+1]->count)

{

tmp = ptrs[from+1];

ptrs[from+1] = ptrs[i];

ptrs[i] = tmp;

}

//pridaj na koniec novy uzol...

ptrs[to]->code = -1;

ptrs[to]->count = ptrs[from]->count +

ptrs[from+1]->count;

ptrs[to]->zero = ptrs[from];

ptrs[to]->one = ptrs[from+1];

ptrs[from]->parent = ptrs[to];

ptrs[from+1]->parent = ptrs[to];

to++;

from += 2;

}

int compress(unsigned char *data, size_t *pLen)

{

Symbol symbols[2*NSYM] = {0};

Symbol* pRoot;

unsigned char *tmp;

char *code;

int