数字javascript的数字之和 [英] sum of the digits of a number javascript

问题描述

我在这个主题上看到了很多其他帖子，但在javascript中没有。这是我的代码。

I saw a bunch of other posts on this topic but none in javascript. here is my code.

var theNumber = function digitAdd (base, exponent) {
    var number = 1;
    for (i=0; i < exponent; i++) {
        var number = base * number;
    }
    return number
}


function find(theNumber) {
 var sum=0;
    parseInt(theNumber);
    while(theNumber>0)
     {
       sum=sum+theNumber%10;
       theNumber=Math.floor(theNumber/10);
      }
    document.writeln("Sum of digits  "+sum);
   }

find(theNumber (2, 50));

我得到了正确答案，我只是不完全理解第二个功能，即声明。任何帮助将不胜感激。谢谢！

I am getting the correct answer, I just don't fully understand the 2nd function, namely the while statement. Any help would be greatly appreciated. Thanks!

推荐答案

第二个函数使用模运算符提取最后一位数字：

The second function uses the modulo operator to extract the last digit:

  1236 % 10
= 1236 - 10 * floor(1236 / 10)
= 1236 - 1230
= 6

提取最后一位数时，会从数字中减去：

When the last digit is extracted, it is subtracted from the number:

  1236 - 6
= 1230

这个数字除以 10 ：

  1230 / 10
= 123

每次循环重复时，最后一位数字被切断并添加到总和。

Each time this loop repeats, the last digit is chopped off and added to the sum.

如果左侧小于右侧（任何1位数字都会发生），则模数运算符返回单个数字，即循环中断：

The modulo operator returns the single digit if the left hand side is smaller than the right (which will happen for any 1-digit number), which is when the loop breaks:

  1 % 10
= 1

这是前导数字加到总数中的方式。

This is how the leading digit gets added to the total.

少数字替代方案是：

function sumDigits(number) {
  var str = number.toString();
  var sum = 0;

  for (var i = 0; i < str.length; i++) {
    sum += parseInt(str.charAt(i), 10);
  }

  return sum;
}

它确实是你要做的，它是迭代数字数字（通过将其转换为字符串）。

It does literally what you are trying to do, which is iterate over the digits of the number (by converting it to a string).

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