C library - rand() function

The C stdlib library rand() function is used to returns the pseudo-random number in the range of 0 to RAND_MAX.

RAND_MAX represents the maximum value that can be returned by the rand() function, and their default value may vary depending on the implementation of the c library. But it is granted to be at least 32767.

Syntax

Following is the C library syntax of the rand() function −

int rand(void)

Parameters

This function does not accepts any parameters.

Return Value

This function returns an integer value that is lies between 0 to RAND_MAX.

Example 1

In this example, we create a basic c program to demonstrate the use of rand() function.

#include <stdio.h>
#include <stdlib.h>

int main() {
   // store the random value
   int rand_value = rand();
   // display the random value
   printf("Random Value: %d\n", rand_value);
   return 0;
}

Following is the output, −

Random Value: 1804289383

Example 2

The below c program used to display the random number within a range using the rand() function.

#include <stdio.h>
#include <stdlib.h>

int main() {
   // display the random value
   int i;
   for(i=1; i<=5; i++)
   {
      printf("%d ", rand());
   }
   return 0;
}

Output

Following is the output −

1804289383 846930886 1681692777 1714636915 1957747793 

Example 3

let's create another example, we are creating a C program to generate random numbers that will be multiples of 10.

#include <stdio.h>
#include <stdlib.h>

int main() {
   // display the random value
   int num = 10;
   int i;
   for(i=1; i<=6; i++)
   {
      printf("%d ", rand()%num);
   }
   return 0;
}

Output

Following is the output −

3 6 7 5 3 5