如何用函数改变变量的值？

Question

I'm building the code for a "Number Guesser Game". How can I change the score after each play?

It's my first unassisted assignment for an online course. I don't have the basic understanding of what to use to achieve certain outcomes so I apologize in advance for the noob question.

I got stuck at task number 5:

Create an updateScore() function. This function will be used to correctly increase the winner's score after each round.

This function:

Has a single parameter. This parameter will be a string value representing the winner. Increases the score variable (humanScore or computerScore) by 1 depending on the winner passed in to updateScore. The string passed in will be either 'human' or 'computer'. Does not need to return any value.

First of all: Why do I need to create a function to change the scoreboard in the first place? Couldn't I just write code to change it after I set the winner in the “compareGuesses” function?

This is what I have so far:

// Write your code below:

let humanScore = 0;
let computerScore = 0;
let currentRoundNumber = 1;


const generateTarget = Math.floor(Math.random() * 9)

const compareGuesses = (humanGuess, computerGuess,targetGuess) => {
  if (Math.abs (humanGuess-targetGuess() )<Math.abs( computerGuess-targetGuess() )){ return true;                                                                        
} else if  (Math.abs (humanGuess-targetGuess() )> Math.abs( computerGuess-targetGuess() )){
  return false; 
}

}


const updateScore = (winner) => {
  if (compareGuesses= true) {
}

Answer 1

First of all: Why do I need to create a function to change the scoreboard in the first place? Couldn't I just write code to change it after I set the winner in the “compareGuesses” function?

Yes, you could do that, but to help with code maintainability (and a number of other things), it is often a good idea to split separate chunks or modules of your larger application/problem into smaller functions. This idea is known as decomposition . Thus, by creating separate functions such as updateScore and compareGuesses you're breaking your bigger problem into smaller more maintainable problems.

---

Now for your updateScore function. Your description says that it will accept a string, either being "human" or "computer" . You need to check whether the winner is either "human" or "computer" and update the associated score variable. Here is an example on how you can achieve this:

const updateScore = (winner) => {
  if(winner === 'human') {
    humanScore += 1; // humanScore++; will also work here
  } else if(winner === 'computer') {
    computerScore += 1; // computerScore++; will also work here
  }
}

Answer 2

So if you wold like to increase player score if he guess the number correctly and increase computer score if the guess is not correct, the function may look like this:

function score(humanScore, computerScore)  {
    if (humanGuess - computerGuess === 0) {
        humanScore += 1
  } 
    else {
        computerScore += 1
   } 
alert(humanScore) 
alert(computerScore) 
}

Of course, you need to call a function like this:

score(humanScore, computerScore)

Answer 3

Try something like this:

class Game {
  humanScore = 0;
  computerScore = 0;
  currentRoundNumber = 1;

  target = 0;

  generateTarget() {
    this.target = Math.floor(Math.random() * 9)
  }

  nextRound(humanGuess, computerGuess) {
    this.currentRoundNumber++;

    if (Math.abs(humanGuess-this.target) < Math.abs(computerGuess-this.target))
      this.humanScore++;                                                  
    else if (Math.abs(humanGuess-this.target) > Math.abs(computerGuess-this.target))
      this.computerScore++;
  }
}

const game = new Game();
game.generateTarget();
game.nextRound(333, 42);

PS: StackOverflow is not here to do your homework. :)