C: Reference

general.c

//copy n integer
//string.h
memcpy(dest,from,sizeof(int)*n);

//memory management
//stdlib.h
void f(){
	int* numberList = (int*) malloc(sizeof(int) * 1000);
	numberList = (int*)realloc(numberList,100);
	//...
	free(numberList); // when function terminates numberList varible disapper but memory remains allocated, so free
}








printf("%d",FOPEN_MAX);//max # of files that can be simultaneously opened
printf("%d",FILENAME_MAX);//max lenght of a filename


//division
//stdlib.h
div_t d;
d = div(9,4);
printf("%d\n",d.quot); //2
printf("%d\n",d.rem);  //1

preprocessor.c

//conditional include

#include "settings.h"

#if VERSION == 0 //defined in settings.h
	#define VERSION_H "test.h"
#elif VERSION == 1
	#define VERSION_H "debug.h"
#else
	#define VERSION_H "production.h"
#endif

#include VERSION_H