[FIXED] How do I get an if statement to check if a user given number is a prime number?

Issue

I am writing a very basic program in Java to check if a number given by the user is a prime number.

I have tried to use an if statement to check if the number divided by itself is equal to 1 as well as if it is divided by 1 it equals itself, but when I run the program and enter a number there is no reaction at all from the if statement.

package prime.java;

import java.util.Scanner;

public class Prime {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("Welcome to Prime!\nPlease enter a number:");
        
        Scanner Scan = new Scanner (System.in);
        int number = Scan.nextInt();
        System.out.println(number);

        if (number%1 == number && number%number == 1) {
            System.out.println(number + " is a prime num");
        }
    }
}

Am I using the right operators?

Solution

This can help you:

static bool isPrime(int number)
    {
        for (int i = 2; i < number; i++)
        {
            if((number% i) == 0)
            {
                // Not Prime
                return false;
            }
        }

        // Just Prime!
        return true;
    }

A prime number is not divisible by any numbers between 2 and (itself - 1).

This way, if you call 'isPrime()' inside the if, this just works.

Hope this can help you!

Answered By - Sergio Quinteiro
Answer Checked By - Mildred Charles (JavaFixing Admin)