Check a number is prime or not?

Problem:- Write a number program to check whether a number is prime or not in Java?

Solution:- Let's see 1st what is a prime number. A number that is greater than 1 and divisible by either 1 or itself only is called a Prime number. For example:- 5 will be divided by only 1 and 5. So, 5 is a prime number.

Java code:- 

package com.codeforsolution.java.logical;

import java.util.InputMismatchException;
import java.util.Scanner;

public class PrimeCheck {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		System.out.println("Enter a number to check prime or not");
		int num;
		try {
			num = s.nextInt();
			if(isPrime(num)) {
				System.out.println(num +" is a Prime number");
			} else {
				System.out.println(num + " is not a prime number");
			}
			
		} catch (InputMismatchException e) {
			System.out.println("Please enter a valid number");
		}
		s.close();
		
	}

	private static boolean isPrime(int num) {
		if(num <= 1) {
			return false;
		} else {
			for(int i=2; i<= num/2; i++) {
				if((num%i)==0) {
					return false;
				}
			}
		}
		return true;
	}

}

Output:- 

Enter a number to check prime or not

12

12 is not a prime number

Enter a number to check prime or not

11

11 is a Prime number