producing random numb in c code example

Example 1: how to genrate a random number in C

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

srand(time(NULL));   // Initialization, should only be called once.
int r = rand();      // Returns a pseudo-random integer between 0 and RAND_MAX.

Example 2: how to genrate a random number in C

srand(time(NULL));
  int r = rand();