功能中的代码在运行时不会运行。如果写在外面的功能

Question

我目前的作业有些问题。

内部代码（while循环）函数startGame（）在函数内部写入时不会运行。如果我删除函数声明它按预期工作。我究竟做错了什么？

let playerScore = 0;
let computerScore = 0;
let playerSelection;
let computerSelection;
let i = 0;

function startGame() {
  while (i < 5) { // This part wont run when used inside function (){}
    playRound();
    i += 1;
  }
}
/*
for (i = 0; i < 6; i++) {
  playRound();
}
*/

/* NOTE TO SELF:
Can't do call to function before declaring variables. 
Since they then would be undefined during runtime. */

function playRound() {
  playerSelection = prompt();
  computerSelection = computerPlay();
  if (playerSelection.trim() === computerSelection.trim()) {
    console.log("Round is Equal")

  } else if (playerSelection === "Scissor" && computerSelection === "Paper") {
    playerScore += 1;
    console.log("Player score is:" + " " + playerScore + " " + "Player wins round");

  } else if (playerSelection === "Paper" && computerSelection === "Scissor") {
    computerScore += 1;
    console.log("Computer score is:" + " " + computerScore + " " + "Computer win round");

  } else if (playerSelection === "Rock" && computerSelection === "Scissor") {
    playerScore += 1;
    console.log("Player score is:" + " " + playerScore + " " + "Player wins round");

  } else if (playerSelection === "Scissor" && computerSelection === "Rock") {
    computerScore += 1;
    console.log("Computer score is:" + " " + computerScore + " " + "Computer win round");

  } else if (playerSelection === "Paper" && computerSelection === "Rock") {
    playerScore += 1;
    console.log("Player score is:" + " " + playerScore + " " + "Player wins round");

  } else if (playerSelection === "Rock" && computerSelection === "Paper") {
    computerScore += 1;
    console.log("Computer score is:" + " " + computerScore + " " + "Computer win round");

  }
}

function computerPlay() {
  let randomNumber = Math.floor(Math.random() * 3) + 1;
  switch (randomNumber) {
    case 1:
      randomNumber = "Rock";
      return randomNumber;
    case 2:
      randomNumber = "Scissor";
      return randomNumber;
    case 3:
      randomNumber = "Paper"
      return randomNumber;
  }

}

Answer 1

你必须调用startGame函数：

startGame()

Answer 2

你需要对startGame()函数进行初始调用，而不是自己运行。

let playerScore = 0;
let computerScore = 0;
let playerSelection;
let computerSelection;
let i = 0;

function startGame() {
  while (i < 5) { // This part wont run when used inside function (){}
    playRound();
    i += 1;
  }
}

startGame();

/*
for (i = 0; i < 6; i++) {
  playRound();
}
*/

/* NOTE TO SELF:
Can't do call to function before declaring variables. 
Since they then would be undefined during runtime. */

function playRound() {
  playerSelection = prompt();
  computerSelection = computerPlay();
  if (playerSelection.trim() === computerSelection.trim()) {
    console.log("Round is Equal")

  } else if (playerSelection === "Scissor" && computerSelection === "Paper") {
    playerScore += 1;
    console.log("Player score is:" + " " + playerScore + " " + "Player wins round");

  } else if (playerSelection === "Paper" && computerSelection === "Scissor") {
    computerScore += 1;
    console.log("Computer score is:" + " " + computerScore + " " + "Computer win round");

  } else if (playerSelection === "Rock" && computerSelection === "Scissor") {
    playerScore += 1;
    console.log("Player score is:" + " " + playerScore + " " + "Player wins round");

  } else if (playerSelection === "Scissor" && computerSelection === "Rock") {
    computerScore += 1;
    console.log("Computer score is:" + " " + computerScore + " " + "Computer win round");

  } else if (playerSelection === "Paper" && computerSelection === "Rock") {
    playerScore += 1;
    console.log("Player score is:" + " " + playerScore + " " + "Player wins round");

  } else if (playerSelection === "Rock" && computerSelection === "Paper") {
    computerScore += 1;
    console.log("Computer score is:" + " " + computerScore + " " + "Computer win round");

  }
}

function computerPlay() {
  let randomNumber = Math.floor(Math.random() * 3) + 1;
  switch (randomNumber) {
    case 1:
      randomNumber = "Rock";
      return randomNumber;
    case 2:
      randomNumber = "Scissor";
      return randomNumber;
    case 3:
      randomNumber = "Paper"
      return randomNumber;
  }

}

Answer 3

你已经创建了一个名为startGame（）的函数，但是你没有在任何地方调用它，这就是它没有在函数中运行的原因。

就像你在循环中调用playRound（）的方式一样，你也必须调用startGame（）来运行它中的代码。