C Program to Check Whether a Number is Prime or Not

Check whether an integer (entered by the user) is a prime number or not using for loop and if...else statement.

	#include <stdio.h>
	int main()
	{
	int n, i, flag = 0;
	printf("Enter a positive integer: ");
	scanf("%d",&n);
	for(i=2; i<=n/2; ++i)
	{
	// condition for nonprime number
	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);
	return 0;
	}

view raw PrimeNumber.c hosted with ❤ by GitHub

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