I’m trying to learn about the loops and the addition assignments such as ++, +=, *=… etc. The problem is I don’t get the logic of it completely if (x+=y = x + y).

Why in the sum= 0 the result is 6 and sum = number is 11? I don’t get where this 6 comes from. Do you know a nice resource to help me on this?

import java.util.Scanner;

public class RepeatingBreakingAndRemembering {

    public static void main(String[] args) {  
        Scanner scanner = new Scanner(System.in);

        System.out.println("Give numbers:");
        int number = Integer.valueOf(scanner.nextLine());
        int sum = 0; // <------ Changing from sum = 0 to sum = number the result are 6 and 11
        
        while (true){
            number = Integer.valueOf(scanner.nextLine());
            if (number == -1){
                break;
            }
            
            sum += number; // sum = sum + number (0 + 5 + 2 + 4 = 11) <------ Shouldnt be like this?
                                                                              //So why the result is 6?
        }
        
    
        System.out.println("Thx! Bye!");
        System.out.println("Sum: " + sum);
    }
}

I expected to happen a result of 11 when using the total sum starting at 0 instead I got a 6 and I don’t know where it comes from.