Thread: Method returning boolean

Assignment:
isPrime Method
A prime number is a number that is only evenly divisible by itself and 1. For example, the number 5 is prime because it can only be evenly divided by 1 and 5. The number 6, however, is not prime because it can be divided evenly 1, 2, 3, and 6.
Write a method named isPrime, which takes an integer as an argument and returns true if the argument is a prime number, or false otherwise. Demonstrate the method in a complete program.

package isprimemethod;
import javax.swing.JOptionPane;
 
/**
 *
 * @author uuuuuuu
 */
public class Main {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        String input;
        int num;
        boolean bool;
 
        input = JOptionPane.showInputDialog("Enter an integer.");
        num = Integer.parseInt(input);
 
        bool = isPrime(num);
        System.out.println(bool);
 
    }
 
    public static boolean isPrime(int num)
    {
        boolean bool;
        {
            if(num%1==0 && num%num==0)
                bool = true;
            else
                bool = false;
        }
        return bool;
    }
}

I tried a few numbers out but the outcome is always "true". No outcome came out to be "false".
What is wrong with the code?

if(num%1==0 && num%num==0)

num%1 means the remainder of num/1 which is 0.

num/num = 1 with remainder 0.

Always true unless perhaps num = 0;

Originally Posted by javapenguin

if(num%1==0 && num%num==0)

num%1 means the remainder of num/1 which is 0.

num/num = 1 with remainder 0.

Always true unless perhaps num = 0;

I know that but, what part of the code do I change in order for it to make certain values to become "false" which is supposed to be false, whereas "true" is true.