SoFunction
Updated on 2025-04-03

JavaScript uses recursion and loop to implement factorial instance code

【Implementation Method】

1. Use a while loop to do it, of course the for loop can be done.

2. Recursion

【Code content】

Be lazy, use the onkeyup event to limit the input of the page

Loop code:

//The first method while loop         = function (){
          var oNum = ('num').value;
          oNum = Number(oNum);
          if(oNum <= 1){
              = 1;
          }
          var oRes = 1;
          while(oNum){
            oRes *= oNum;
            oNum--;
          }
           = oRes;
        }

Recursive code

// The second method recursion       = function(){
        var oNum = ('num').value;
        oNum = Number(oNum);
        function factorial (num) {
          if (num <= 1) {
            return 1;
          } else {
            return (num * factorial(num-1));
          }
        };
        oRes=factorial(oNum);
         = oRes;
      };

Complete code:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Two factorial methods</title>
  <style>
    #box {
      width: 100%;
      height: 200px;
      border: 1px solid #ccc;
      text-align: center;
    }
  </style>
  <script>
     = function() {
       var oBox = ('box');
       var oCount = ('count');
      // The first method while loop      //   = function (){
      //     var oNum = ('num').value;
      //     oNum = Number(oNum);
      //     if(oNum <= 1){
      //        = 1;
      //     }
      //     var oRes = 1;
      //     while(oNum){
      //       oRes *= oNum;
      //       oNum--;
      //     }
      //      = oRes;
      //   }
    // The second method       = function(){
        var oNum = ('num').value;
        oNum = Number(oNum);
        function factorial (num) {
          if (num <= 1) {
            return 1;
          } else {
            return (num * factorial(num-1));
          }
        };
        oRes=factorial(oNum);
         = oRes;
      };
    }
  </script>
</head>
<body>
  <div ></div>
  <input type="text"  onkeyup="value=(/[^0-9]/g,'')" onpaste="value=(/[^0-9]/g,'')" oncontextmenu = "value=(/[^0-9]/g,'')">
  <input type="button"  value="calculate">
</body>
</html>

Let's see below through the codeJavaScript intermediate factorial function method

I haven't done it for a long time, practice:

// First, the calculation method of the hierarchical function added upwards var number = function(n) {
  if(n == 1) {
    return 1
  } else {
    product = 1;
    for(i = 1; i <= n; i++) {
       product *= i;
    }
    return product;
  }
}
var d = number(5);
alert(d);
 // Second, the hierarchical function that subtracts downwardvar del = function(n) {
    if(n == 1) {
       return 1
    } else {
       return n * del(n - 1);
    }
  }
  var data= del(5);
  alert(data);

Summarize

The above is the example code of JavaScript using recursion and loop to implement factorials. I hope it will be helpful to you. If you have any questions, please leave me a message and the editor will reply to you in time. Thank you very much for your support for my website!