Home C Language Basic C Programs Prime Number Program in C using Function

Prime Number Program in C using Function

Write a program in C to check whether a number is a prime number or not using the functions.



bool isPrime(int);

int main()


   int n; /*’n’ is user defined number.*/

   printf(“Enter a number :”);


   if(isPrime(n)) /*if isPrime() return’s TRUE, then if statement will execute otherwise else will execute*/

      printf(“Given number is PRIME number\n”);


      printf(“Given number is Non-PRIME number\n”);

   return 1;


bool isPrime(int n)


    int i,count;




      if(n%i==0) /*check the iteration value is factor of given number or not.*/




        return 1; /*true & false are defined words from “stdbool.h” we can also use 1 & 0*/

    return 0; /*Here we did not use “else” because when a “return” statement appears Compiler automatically terminates the function and returns the value, so when the if condition fails then only “return 0” will execute*/



i) Enter a number : 7919

Given number is PRIME number

ii)Enter a number : 852

Given number is Non-PRIME number

Other Prime number programs

Write a C Program to Find Whether the Given Number is Prime Number or not.

Write a C program to generate first ‘n’ prime numbers, where n is a value Supplied by the user.