Hangman Game Javascript：如果猜到单词中的最后一个字符，则单词完成

Question

I am coding a hangman game for a class assignment. The wordcheck() function, which compares the index of the characters of the word to the index of the spaces, is not working as it should. If the user guesses a letter in the middle of the word, the letter will fill the _ space just as it should. However, if the user guesses the last letter of the word, it will automatically go to the win screen and reveal the full word even if the spaces before do not match. I am positive the problem is in this function. I believe it's because the loop runs for however long the characters list is (or how long the word is) and if the last value returns as equal to the last value in the spaces list, it will return as true even if the previous values return as unequal. Still, even if this is the problem, I have no idea how to fix it.

Thank you!

function wordCheck() {
    var wordComplete = false;
    for (var i = 0; i < letters.length; i++) {
        if (letters[i] !== blanks[i]) {
            wordComplete = false;
        }
        else {
            wordComplete = true;
        }
    }
    if (wordCompleted == true) {
        gameWon();
    }
}

Answer 1

The problem is, you need to set the value of true ONLY if the condition for true exists (and in this case, you only know that for a fact AFTER you have evaluated all the characters and spaces). In your code, you set to either true or false EVERY time you evaluate a characters/space match (which means you can unset the result you are looking for). This little logic trap gets coders all the time.

Consider it this way: I get to ask your name five times, and I only have to get it right once to win, but I always have to guess five times (after which you will tell me if one of my guesses was correct). If you evaluate my answer each time, and the last answer is wrong, it will never matter if I ever got it right. It will only work if the last guess is correct. So you would either stop evaluating answers once I've guessed correctly, of you would wait for all five guesses and THEN determine if I win/lose.

In your case, you require that all "guesses" be made before determining win/lose. So you just track them, and afterwards, make the win/lose decision.

So you'd do something like this:

function wordCheck(){
    // track the matches
    var matches = 0;
    for ( var i = 0; i < spaces.length; i++ ) { 
       // If there's a match, increment matches. Else, leave it alone.
       matches = ( characters [ i ] === spaces [ i ] ? matches + 1 : matches );
    }
    // Now that you have evaluated ALL matches, you can make the decision.
    // If matches === your spaces length, all matches were found, return true, else false
    return ( matches === spaces.length );
}

Answer 2

function wordCheck() {
    wordCompleted = true; //set it to true first,
    for (var i = 0; i < characters.length; i++) {
        if (characters[i] !== spaces[i]) {
            wordCompleted = false; //then, if a single char is false, set it to false
        }
    }
    if (wordCompleted == true) {
        gameWon();
    }
}

Your issue was that you were setting wordCompleted to true if a letter was right. This meant that if only the last letter was correct, it would still be set to true (there were no false letters after to set it to false)

Answer 3

Yes, indeed your function is changing the value of wordCompleted in each iteration. If the last char matches, then wordCompleted is true , and you call gameWon() . I think the expected behavior would be if just call gameWon() when the whole word is guessed, right? I think this version of your function make what you want.

function wordCheck(){
    let i = 0;
    while(i < characters.length && characters[i] === spaces[i]){
        i++; 
    }

    const wordCompleted = i === characters.length;
    if (wordCompleted == true) {
        gameWon();
    }
}

Now with this function, we are iterating over the characters and spaces arrays until their elements are different or the whole array was iterated. Then we just check if we reach the last element, if yes, the game is won.

Answer 4

If there is a correct letter after a bad letter your script says all your word is correct because you will set the boolean for each letters hence override the bad letter check.

So just define a boolean to true at the beginning and then set it to false if a letter if wrong but don't set it back to true if the letter is right. At then end if your boolean is false , it means one of your letter is wrong.

function wordCheck(){
  var wordCompleted = true;
  for (var i = 0; i < characters.length; i++) {
    if (characters[i] !== spaces[i]) {
      wordCompleted = false;
    }
  }
  if (wordCompleted == true) {
    gameWon();
  }
}

Answer 5

You're partially correct that the problem is that you continue through the loop to the end - the thing is, the way you've set up the function means that only the last character matters.

What you really care about though, is how many of the characters in the entire word match.

Take a look at this function:

function wordCheck(){
  var correctCharacters = 0;
  for (var i = 0; i < characters.length; i++) {
    if (characters[i] === spaces[i]) {
      correctCharacters ++;
    }
  }
  if (correctCharacters === characters.length) {
    gameWon();
  }
}