if, else if, else trouble

[John Vorona]

Hello, I am trying to compile this program and i keep receiving an error. I can't figure out what the problem is, perhaps I need another pair of eyes to look at it.
Anyways here is my code:

import java.util.Scanner;

public class UserInput {
	public static void main(String[] args){
		
		String ifElseCase;
		
		Scanner in = new Scanner(System.in);
		
		System.out.print("Enter an integer: ");
		int num = in.nextInt();
		
		if (num <20) {
			ifElseCase = "Your number is less than 20";
		}
		else if (num = 20) {
			ifElseCase = "Your number is 20";
		}
		else {
			ifElseCase = "Your number is greater than 20";
		}
			System.out.println(ifElseCase);
		
	}
}

And here is the error message i get when i compile it via command prompt:

C:\Users\Naz\Java\Random>javac UserInput.java
UserInput.java:16: error: incompatible types
                else if (num = 20) {
                             ^
  required: boolean
  found:    int
1 error

I've declared the variable num as an integer, why is it asking for boolean?

[fred rosenberger]

do you know the difference between '=' and '==' in java? Note: java is different from C (if you are familiar with that language - if not, don't worry about it).

[John Vorona]

Right, i completely forgot about this. The program works properly now.

Just to clarify, in Java "==" means true equality, where as "=" is simply assignment?

[Joel Christophel]

Nazar Buko wrote:Right, i completely forgot about this. The program works properly now.

Just to clarify, in Java "==" means true equality, where as "=" is simply assignment?

Yes.
As for "==", it is mostly used to test equality between primitive types (e.g. int, char). equals() is used when testing the equality of objects (e.g. Strings and mostly everything). When used between objects, "==" only returns true if the left and right refer to the exact same object. The following would print false then true:

		String x = new String("string");
		String y = new String("string");
		
		System.out.println(x == y);
		System.out.println(x.equals(y));

[John Vorona]

Joel Christophel wrote:

		String x = new String("string");
		String y = new String("string");
		
		System.out.println(x == y);
		System.out.println(x.equals(y));

I see, the first one would be false since x and y are different instances of the String object. Where as x.equals(y) simply means, x and y have the same values.

[Joel Christophel]

Nazar Buko wrote:
I see, the first one would be false since x and y are different instances of the String object. Where as x.equals(y) simply means, x and y have the same values.

Correct.

[John Vorona]

Thanks all.