Programming

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(void)
{
        int n;
        srand(time(NULL));
        for(n=0; n<4; n++)  printf("%04d", rand()%10000);
}

#include <stdio.h>

typedef
union
{
	char tmp[sizeof(unsigned long long)];
	unsigned long long myll;
} ll_t;


unsigned long long llrand(void)
{
	FILE *in=fopen("/dev/urandom", "r");
	ll_t ll_u;
	fread(ll_u.tmp, sizeof(ll_u.tmp), 1, in);
	fclose(in);
	return ll_u.myll;
}

int main()
{
	char tmp[64]={0x0};
	char working[64]={0x0};
	int i=0;
		
	for(i=0; i< 20; i++)
	{
		while(strlen(tmp) < 16)
		{
			sprintf(working, "%lu", llrand() );
			strcat(tmp, working);
		}
		tmp[16]=0x0;
		printf("%s\n", tmp);
		*tmp=0x0;
	}
	return 0;
}