rand()

Generates a pseudo-random integer value.

  #include <stdlib.h>
  
  int rand(void);

Remarks

A sequence of calls to the rand() function generates and returns a sequence of pseudorandom integer values from 0 to RAND_MAX. The RAND_MAX macro is defined in stdlib.h.

By seeding the random number generator using srand(), different random number sequences can be generated with rand().

rand() returns a pseudo-random integer value between 0 and RAND_MAX.

Listing: Example of rand() usage


#include <stdlib.h>

#include <stdio.h>

int main(void)

{

int i;

unsigned int seed;

for (seed = 1; seed = 5; seed++) {

srand(seed);

printf("First five random numbers for seed %d:\n", seed);

for (i = 0; i < 5; i++)

printf("%10d", rand());

printf("\n\n");

}

return 0;

}

Output:

First five random numbers for seed 1:

16838 5758 10113 17515 31051

First five random numbers for seed 2:

908 22817 10239 12914 25837

First five random numbers for seed 3:

17747 7107 10365 8312 20622

First five random numbers for seed 4:

1817 24166 10491 3711 15407

First five random numbers for seed 5:

18655 8457 10616 31877 10193