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.

#include<stdio.h>

#include<stdbool.h>

bool isPrime(int);

int main()

{

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

printf(“Enter a number :”);

scanf(“%d”,&n);

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

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

else

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

return 1;

}

bool isPrime(int n)

{

int i,count;

count=0;

for(i=1;i<=n;i++)

{

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

count++;

}

if(count==2)

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*/

}

Output:

i) Enter a number : 7919

Given number is PRIME number

ii)Enter a number : 852

Given number is Non-PRIME number