rand() is a Utility Function that is used to generate pseudo random numbers. Every time this function returns a integer between the range zero and RAND_MAX is returned.

   int rand(void);  

   #include <stdlib.h>
   #include <stdio.h>
   int main()
     {
       int r;
       for(r=0;r<5;r++)
         {
            printf("The random integer is:: %d\n", rand());
         }
       return 0;
     }

    The random integer is:: 130	
    The random integer is:: 10982
    The random integer is:: 1090
    The random integer is:: 11656
    The random integer is:: 7117

In the above example rand() function returns random numbers between 0 and 5.