Question

运行代码时，它不会乘以我的数字，只是循环输出直到达到1

我尝试了多种不同的方法，而这是我获得的最接近的方法

    ......................................
    var BR="<br />"; //html line break

    function factorial(Num) {

   document.write("The factorial of your number is" +Num +BR);

   if (Num == 1 ) return 1;

   else return (Num * factorial(Num-1));

    }
.....................................................        





   .......................................
        var Num; //users number
        var Numfactorial;
        var ES="";
               var factorial                     
        Num=prompt("Enter a number between 1-20" +ES);
        Numfactorial=factorial(Num);
     .........................................

应该将数字乘以下来，所以说您输入20，它应该向下移19 * 18 * 17 ...向下乘以1，然后输出乘积。

Answer 1

将document.write放在函数之外，然后仅将结果（Numfactorial）打印到页面上。您还需要将Num解析为一个数字，然后删除var factorial：

var BR = "<br />";
function factorial(Num) {
    if (Num == 1) return 1;
    else return Num * factorial(Num - 1);
}
var Num;
var Numfactorial;
var ES = "";
Num = parseInt(prompt("Enter a number between 1-20" + ES));
Numfactorial = factorial(Num);
document.write("The factorial of your number is " + Numfactorial + BR);

Answer 2

好吧，这就是代码的预期输出。函数阶乘正在返回您未使用的值以显示该值。您应该这样写：

....................................................
var BR="<br />"; //html line break
function factorial(Num) {
   if (Num == 1 ) return 1;
   else return (Num * factorial(Num-1));
}
.....................................................



.......................................
    var Num; //users number
    var Numfactorial;
    var ES="";
           var factorial                     
    Num=prompt("Enter a number between 1-20" +ES);
    Numfactorial=factorial(Num);
    document.write("The factorial of your number is" +Numfactorial +BR);
 .........................................

阶乘不会相乘

2 个答案: