javascript - 如果语句不起作用

Question

我是js新手，我只是根据石头剪刀布游戏写了下面的基本功能。由于某种原因，比较函数的结果总是显示为“平局”而不是其他结果。我在这里做错了什么？

var userChoice = prompt("Do you choose rock, paper or scissors?");
var computerChoice = Math.random();

if (computerChoice < 0.34) {
    computerChoice = "rock";
} else if (computerChoice <= 0.67) {
    computerChoice = "paper";
} else {
    computerChoice = "scissors";
}

choice1 = userChoice;
choice2 = computerChoice;

var compare = function (choice1, choice2) {
if (choice1 == choice2) {
        return "draw!";
}

if (choice1 == "rock") {
    if (choice2 == "scissors") {
        return "rock wins!";
    } else {
        return "paper wins!";
    }
}

if (choice1 == "paper") {
    if (choice2 == "scissors") {
        return "scissors wins!";
    } else {
        return "paper wins!";
    }
}

    if (choice1 == "scissors") {
        if (choice2 == "rock") {
            return "rock wins!";
        } else {
            return "scissors wins!";
        }
    }
};

compare();

谢谢，我们

Answer 1

您正在调用不带参数的比较：

compare();

因此choice1，choice2两者都相等undefined，您的游戏将始终以平局告终。您应该尝试像这样调用您的比较函数：

compare(userChoice, computerChoice);

如果定义函数，参数列表定义函数范围内给定变量的名称。这不是函数本身应该可用的变量的命名约定。

Answer 2

您已经使用两个参数定义了函数：

var compare = function (choice1, choice2) 

但是你已经用 0 调用了它。

尝试指定选项：

compare("rock", "paper");

Answer 3

您不能仅通过键入不带参数的 func_name() 来打开功能，就像“干炮”一样。阅读函数声明

var userChoice = prompt("Do you choose rock, paper or scissors?");
var computerChoice = Math.random();
if (computerChoice < 0.34) {
  computerChoice = "rock";
} else if (computerChoice <= 0.67) {
  computerChoice = "paper";
} else {
  computerChoice = "scissors";
}
choice1 = userChoice;
choice2 = computerChoice;
function compare (choice1, choice2) {
  if (choice1 == choice2) {
    return "draw!";
  };
  if (choice1 == "rock") {
    if (choice2 == "scissors") {
      return "rock wins!";
    } else {
      return "paper wins!";
    }
  }
  if (choice1 == "paper") {
    if (choice2 == "scissors") {
      return "scissors wins!";
    } else {
      return "paper wins!";
    }
  }
  if (choice1 == "scissors") {
    if (choice2 == "rock") {
      return "rock wins!";
    } else {
      return "scissors wins!";
    }
  }
};
compare(choice1, choice2);