Simple C Program to Check Whether given Number is Prime or Not

     

   

   Prime Number - defn

        

                 A Prime Number can be divided evenly only by 1, or itself. And it must be a whole number greater than 1. 

•  Most of the new c language beginers didnt know to code for checking prime number or not
• Here this blog tell the logic of prime number check

C-Code

#include <stdio.h>

main()

{

    int n, i, flag = 0;

    printf("Enter a positive integer: ");

    scanf("%d",&n);

    for(i=2; i<=n/2; i++)

    {

        if(n%i==0)

        {

            flag=1;

            break;

        }

    }

    if (flag==0)

        printf("%d is a prime number.",n);

    else

        printf("%d is not a prime number.",n);

    

}

1. %   it will return  number that the  remainder of the division ( / it will return quotient of division)
2. (flag) is a simple variable that keeps on checking the state of any operation at any iteration.
3. using modulus operator ,get the remainder if the remainder is not equal to 0 
4. then the flag is set to 0 ,at end of for loop flag  value is 0.
5. then display the message as prime number.

this is a simple logic for prime number checking,if u have further doubts commend me