Header File 

stdlib.h  

Category 

Math Routines 

Prototype 

int rand(void); 

Description 

Random number generator. 

rand uses a multiplicative congruential random number generator with period 2 to the 32nd power to return successive pseudo-random numbers in the range from 0 to RAND_MAX. The symbolic constant RAND_MAX is defined in stdlib.h. 

Return Value 

rand returns the generated pseudo-random number. 

Example  

#include <stdlib.h>
#include <stdio.h>
int main(void)
{
    int i;
    randomize();
    printf("Ten random numbers from 0 to 99\n\n");
    for(i=0; i<10; i++)
       printf("%d\n", rand() % 100);
    return 0;
}

Portability