JavaScript：石头剪刀布。函数错误答案

【问题标题】：JavaScript: rock paper scissors. Function errorJavaScript：石头剪刀布。函数错误
【发布时间】：2021-02-28 12:17:54
【问题描述】：

我试图在 JavaScript 中创建游戏“石头、剪纸或剪刀”，但我卡在最后一个函数“game()”上，它应该重复函数 playRound() 5 次，并分别抛出这 5 个结果次。但是没用。

function computerPlay(){
    let optionsList = ["rock", "paper", "scissors"];
    let option = optionsList[Math.floor(Math.random() * optionsList.length)];
    return option
}

function playRound(playerSelection, computerSelection){
    var playerSelection = prompt("Choose: rock, paper or scissors").toLowerCase();
    var computerSelection = computerPlay();

    if (playerSelection = "rock"){
        switch(computerSelection){
            case "rock":
                return "T";
            case "paper":
                return "M";
            case "scissors":
                return "Y";
        }
    }else if (playerSelection = "paper"){
        switch(computerSelection){
            case "rock":
                return "Y";
            case "paper":
                return "T";
            case "scissors":
                return "M";
        }
    }else if (playerSelection = "scissors"){
        switch(computerSelection){
            case "rock":
                return "M";
            case "paper":
                return "Y";
            case "scissors":
                return "T";
        }
    }
}

function game(){
    let i = 0
    for(i=1; i<=5; i++){
        playRound()
        if (playRound()= "M") {
            console.log("Machine Wins");
        }else if (playRound() = "Y"){
            console.log("You Win")
        }else if (playRound() = "T"){
            console.log("You Win!")
        }
    }
}

【问题讨论】：

标签： javascript

【解决方案1】：

你有几个错误：

首先是您尝试使用= 运算符来比较值。您需要使用== 或===。
其次，你需要得到playRound()的返回值，然后检查它的值来确定游戏的结果。但是，您最初是在循环的每次迭代中调用 playRound()，然后在每次尝试确定结果时再次调用。

试试：

function computerPlay() {
  let optionsList = ["rock", "paper", "scissors"];
  let option = optionsList[Math.floor(Math.random() * optionsList.length)];
  return option
}

function playRound(playerSelection, computerSelection) {
  var playerSelection = prompt("Choose: rock, paper or scissors").toLowerCase();
  var computerSelection = computerPlay();

  if (playerSelection === "rock") {
    switch (computerSelection) {
      case "rock":
        return "T";
      case "paper":
        return "M";
      case "scissors":
        return "Y";
    }
  } else if (playerSelection === "paper") {
    switch (computerSelection) {
      case "rock":
        return "Y";
      case "paper":
        return "T";
      case "scissors":
        return "M";
    }
  } else if (playerSelection === "scissors") {
    switch (computerSelection) {
      case "rock":
        return "M";
      case "paper":
        return "Y";
      case "scissors":
        return "T";
    }
  }
}

function game() {
  let i = 0
  for (i = 1; i <= 5; i++) {
    let outcome = playRound()
    if (outcome === "M") {
      console.log("Machine Wins");
    } else if (outcome === "Y") {
      console.log("You Win")
    } else if (outcome === "T") {
      console.log("You Win!")
    }
  }
}

game();

【讨论】：

【解决方案2】：

不确定这是否能解决问题，但这里有一个语法错误：= 而不是 ==。此外，您不应在每个else 中调用playRound()。只需将结果存储在变量中即可。

 let result = playRound()
 if (result== "M") {                              
        console.log("Machine Wins");
 }else if (result == "Y"){
        console.log("You Win")             
 }else if (result == "T"){
        console.log("You Win!")
 }

【讨论】：