The function **int rand(void);** returns a pseudo random integer number between 0 and RAND_MAX. RAND_MAX is a constant defined in stdlib standard library, it's value is library dependent, but is guaranteed to be at least 32767. The function rand uses a seed to generate the series, which should be initialize using srand. If seed remains the same, then rand function generates same sequence of random numbers.

**In range of 0 - N**: rand() % N+1.**In range of 1 - N**: (rand() % N) + 1.**In range of N - M**: (rand() % M-N+1) + N.

## Function prototype of rand

*int rand(void);*## Return value of rand

This function returns an integer between 0 and RAND_MAX.

## C program using rand function

The following program shows the use of rand function to generate a sequence of pseudo random numbers.

#include <stdio.h> #include <stdlib.h> int main(){ unsigned int seed; int n, counter; printf("Enter a unsigned number(seed)\n"); scanf("%u", &seed); /* Initialize random number generator using srand */ srand(seed); printf("Enter number of random numbers\n"); scanf("%d", &n); for(counter=0; counter < n; counter++){ printf("%d ", rand()); } return 0; }

Output

Enter a unsigned number(seed) 234 Enter number of random numbers 7 802 32478 7150 29924 30401 13148 15783