What is the use of randomize and srand functions in C language?

If we are generating random numbers in a program, it is necessary to control the series of numbers.

The randomize() and srand() functions are used to seed the random number generator.

The process of assigning the random number generators starting number is called seeding the generators.

• The randomize() uses PC’s clock to produce a random seed.

• srand() allows us to specify the random number generator’s starting value.

Program

Given below is the C program on rand −

 Live Demo

#include<stdio.h>
int main(){
   // create same sequence of
   // random numbers on every time the program runs
   for(int i = 0; i<10; i++)
      printf(" %d ", rand());
   return 0;
}

Output

You will see the following output −

1804289383
846930886
1681692777
1714636915
1957747793
424238335
719885386
1649760492
596516649
1189641421

Following is the C program on srand −

 Live Demo

#include <stdio.h>
#include <stdlib.h>
#include<time.h>
int main(){
   // create different sequence of
   // random numbers on every time the program runs
   // It Use current time as seed for random generator
   srand(time(0));
   for(int i = 0; i<10; i++)
      printf(" %d ", rand());
   return 0;
}

Output

You will see the following output −

1919778910
1203408690
1755813469
1976428341
37040990
1849384103
986990763
2040061815
391541163
1718314135