为什么我的函数 if/else if/else if 语句返回相同的答案？

Question

我设置了一个石头、纸、剪刀游戏，用户点击标记为“石头”、“纸”、“剪刀”的按钮，这会导致用户选择。 当我运行程序时，compareChoices() 函数总是返回“结果是平局，让我们再玩一次！”，我不明白为什么。

  < article >
    < button onclick = "rockPaperScissors('Rock')" > Rock < /button>
    <button onclick="rockPaperScissors('Paper')">Paper</button >
    < button onclick = "rockPaperScissors('Scissors')" > Scissors < /button>
  </article >

    < script type = "text/javascript" >
    function rockPaperScissors(userchoice) {
      alert("You chose " + userchoice + " ...the computer chose " + getComputerChoice() + ".");
      compareChoices();
    }

  function getComputerChoice() {
    var computerChoice = Math.random();
    if (computerChoice < 0.34) {
      computerChoice = "Rock";
    } else if (computerChoice < 0.67) {
      computerChoice = "Paper";
    } else {
      computerChoice = "Scissors";
    }
    return computerChoice;
  }

  function compareChoices(userChoice, ComputerChoice) {
    if (userChoice === ComputerChoice) {
      alert("The result is a tie, let's play again!");
    } else if (userChoice === "Rock") {
      if (ComputerChoice === "Scissors") {
        alert("Congratulations, you win!");
      } else {
        alert("The computer wins! Care to play again?");
      }
    } else if (userChoice === "Scissors") {
      if (ComputerChoice === "Rock") {
        alert("The computer wins, let's play again!");
      } else {
        alert("Yippie! You win!");
      }
    } else if (userChoice === "Paper") {
      if (ComputerChoice === "Rock") {
        alert("The computer wins. Don't give up, try again!");
      } else {
        alert("Hail the all mighty visitor. Give it another go!");
      }
    }
  } < /script>

Answer 1

您没有将任何内容传递给 compareChoices

  < article >
    < button onclick = "rockPaperScissors('Rock')" > Rock < /button>
    <button onclick="rockPaperScissors('Paper')">Paper</button >
    < button onclick = "rockPaperScissors('Scissors')" > Scissors < /button>
  </article >

    < script type = "text/javascript" >
    function rockPaperScissors(userchoice) {
      var computerChoice = getComputerChoice();
      alert("You chose " + userchoice + " ...the computer chose " + computerChoice + ".");
      compareChoices(userChoice, computerChoice);
    }

  function getComputerChoice() {
    var computerChoice = Math.random();
    if (computerChoice < 0.34) {
      computerChoice = "Rock";
    } else if (computerChoice < 0.67) {
      computerChoice = "Paper";
    } else {
      computerChoice = "Scissors";
    }
    return computerChoice;
  }

  function compareChoices(userChoice, ComputerChoice) {
    if (userChoice === ComputerChoice) {
      alert("The result is a tie, let's play again!");
    } else if (userChoice === "Rock") {
      if (ComputerChoice === "Scissors") {
        alert("Congratulations, you win!");
      } else {
        alert("The computer wins! Care to play again?");
      }
    } else if (userChoice === "Scissors") {
      if (ComputerChoice === "Rock") {
        alert("The computer wins, let's play again!");
      } else {
        alert("Yippie! You win!");
      }
    } else if (userChoice === "Paper") {
      if (ComputerChoice === "Rock") {
        alert("The computer wins. Don't give up, try again!");
      } else {
        alert("Hail the all mighty visitor. Give it another go!");
      }
    }
  } < /script>

Answer 2

你必须把computerchoice放入变量中，然后用相同的computerchoice调用comparechoices函数。

function rockPaperScissors(userchoice) {
       var computerchoice = getComputerChoice();
       alert("You chose " + userchoice + " ...the computer chose " + computerchoice + ".");
       compareChoices(userchoice, computerchoice);
    }

Answer 3

您需要将参数传递给 compareChoices()。

function rockPaperScissors(userchoice) {
      alert("You chose " + userchoice + " ...the computer chose " + getComputerChoice() + ".");
      compareChoices(userchoice, getComputerChoice());
    }

您应该只提醒一次，因为它们会靠得很近。像这样的：

function compareChoices(userChoice, ComputerChoice) {
    var message;
    if (userChoice === ComputerChoice) {
      message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - The result is a tie, let's play again!";
    } else if (userChoice === "Rock") {
      if (ComputerChoice === "Scissors") {
        message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - Congratulations, you win!";
      } else {
        message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - The computer wins! Care to play again?");
      }
    } else if (userChoice === "Scissors") {
      if (ComputerChoice === "Rock") {
        message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - The computer wins, let's play again!";
      } else {
        message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - Yippie! You win!";
      }
    } else if (userChoice === "Paper") {
      if (ComputerChoice === "Rock") {
        message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - The computer wins. Don't give up, try again!";
      } else {
        message = "Computer: " + ComputerChoice + ", User: " + userChoice + " - Hail the all mighty visitor. Give it another go!";
      }
    }
  alert(message);
}