我的提示代码不起作用

Question

我正在制作一个简单的JS计算器。但是，变量中的提示不会出现。是的，我会将孩子的功能改变成变量，以使开关语句成为可能。但即使将它打成JS固定器，它也不起作用。任何人都可以告诉我该怎么做？我有点卡在这里。我曾尝试把它放入JSFiddle，但它仍然没有奏效。谢谢，如果我得到答案！

var firstNumber = prompt("Type in the first number that you want to add,subtract,divide,multiply,power(square or to the power of) or square root."); 

    var operationForNumber() = prompt("Type in the symbol that matches the operation that you want to use(2 for square, ! for square root, /,for division and a * for multiplication)."); 

    var secondNumber() = prompt("Type in the second number that you want to add,subtract,divide,multiply,square or square root."); 


    switch (operationForNumber) { 
     case +: 
      firstNumber "+" 
      secondNumber 
      break; 
     case -: 
      firstNumber "-" 
      secondNumber 
      break; 
     case /: 
     firstNumber "/" 
     secondNumber 
     case *: 
      firstNumber "*" 
      secondNumber 
      break; 
     case 2: 
      Math.pow(firstNumber, secondNumber); 
      break; 
     case !: 
      sqrt(firstNumber) 
     default: 
      console.log("The number you have typed is too great to be calculated or the operation that you chose(+,/,-,X) isn't valid!"); 
    } 

Answer 1

您的代码失败，因为您没有在switch-cases中的运算符周围引用引号。这样做对所有的案件：

case "+": 
case "-": 

等

Answer 2

你必须存储在变量提示符调用的结果，使它们可用于开关内的语句。

var firstNumber = prompt("Type in the first number that you want to add,subtract,divide,multiply,power(square or to the power of) or square root."); var operationForNumber = prompt("Type in the symbol that matches the operation that you want to use(2 for square, ! for square root, /,for division and a * for multiplication)."); var secondNumber = prompt("Type in the second number that you want to add, subtract, divide, multiply, square or square root."); 此外请坚持一致的代码风格并用分号终止语句。