同时执行条件不会停止循环

Question

I've programmed a Hangman game containing a do-while loop to keep asking the user for letters until they either solved the word or ran out of lives. The weird thing is that the loop doesn't stop when the conditions are met.

Here's the implementation of the game logic containing the loop:

String letter;
int result = 0;

do {
    displayWord();

    System.out.println("Please enter a letter: ");
    letter = scan.next().toLowerCase();

    if (letter.matches("[a-z]")) {
        result = hg.process(letter);
        displayResult(result);
    } else {
        System.out.println("Sorry, not a valid input.");
    }
}
while(result != 2 || result != -2); 

The variable result is getting the return value from the process method. Here's the implementation.

public int process(String letter) {
    boolean found = false;

    //... some code here

    if(!found) {
        if(lifeLine == 0) {
            return gameOver; // no lives left
        } else {
            lifeLine--;
            return wrong; // wrong guess
        }
    } else if (found && this.answer.equals(this.rightAnswer)) {
        return complete; // complete game
    } else {
        return right; // right answer, but incomplete game
    }
}

Could it be the way how I'm returning the values that's causing the loop to keep looping? I've declared these values like this:

public static final int right = 1;
public static final int wrong = -1;
public static final int complete = 2;
public static final int gameOver = -2;

Answer 1

Logically, by De Morgan's law ,

result != 2 || result != -2

is the same as

!(result == 2 && result == -2)

which is always a true expression.

---

The condition should probably be

!(result == complete || result == gameOver)

which, when applying the same law as above, is

result != complete && result != gameOver

(Using the constants - although I would prefer uppercase symbols like GAMEOVER - instead of the magic numbers also makes the code easier to read.)

Answer 2

 while(result != 2 || result != -2); 

Lets think about this for a second. If the result is 2 then the right part of the OR is true (result is not equal to -2). And if the result is -2 then the left side of the OR is true (result is not equal to 2).