C rand()

The rand() function is defined in the stdlib.h header file. This function is used for Pseudo Random Number Generator(PRNG) within the range 0 to RAND_MAX. The RAND_MAX is a symbolic constant, depending on the C libraries its value greater but not less than 32767.


int rand(void); 

 

rand() Parameters: 

The rand() function does not take any parameter.

rand() Return Value

The rand() function return value is an integer value between 0 and RAND_MAX.

Input Return Value
success integer value(0- RAND_MAX)

Examples of rand() 

Example 1: Working of rand() function in C?


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

int main()
{
   int k, num;
   time_t tm;
   
   num = 5;
   
   /* Intializes random number*/
   srand((unsigned) time(&tm;));

   /* random numbers from 0 to 49 */
   for( k = 0 ; k < num ; k++ ) {
      printf("%d\n", rand() % 50);
   }
   
   return(0);
}

Output:


38
45
29
29
47

Example 2: How rand() works in error case?


#include <stdio.h>
#include <stdlib.h>
int main (){
    printf (" Random number is: %d", rand());  
    printf ("\nRandom number is: %d", rand());  
      
    printf (" \n Random number is: %d", rand());  
    printf ("\n Random number is: %d", rand());  
    getch(); 
}

Output:


 Random number is: 41
 Random number is: 18467
 Random number is: 6334
 Random number is: 26500