如何使用while循环求和保存为JavaScript中数组的数字 [英] How to sum numbers saved as array in JavaScript with while loop

问题描述

错误在哪里？我想对数组中的每个数字求和。警报显示 NaN 。

Where is the mistake? I want to sum every number in the array. The alert says NaN.

var numbers = [10, 42, 5, 87, 61, 34, 99];
var i = 0; 
var e = 0;
while(i <= numbers.length) {
    e = e + numbers[i]; 
    i++;
}

alert(e);

推荐答案

问题出在数组长度中您正在检查因为数组索引以0开头。这样做时：

The problem is in array length You are checking because array index starts with 0. In that way when doing:

i <= numbers.length

您正在检查[0：10，1：42，2：2：5，3：87，4：61，5：34，6 ：99，7：???]，因为数字长度为7。要解决该问题，只需执行以下操作：

You are checking [0: 10, 1: 42, 2: 5, 3: 87, 4: 61, 5: 34, 6: 99, 7:???] because numbers length is 7. To solve it just do:

i < numbers.length 

其中，您不检查数组中不存在的数字。

where You don't check non existing number in array.

这是我们在学校的想法：

Here is how we were thought in school:

//main code//
var numbers = [10, 42, 5, 87, 61, 34, 99];
var result = sumIntArray(numbers);
//end of main code//

function sumIntArray(array){
    var result = 0;
    for (var i = 0; i < array.length; i++) {
        if (array[i].isInteger()) {
            result += array[i];
        } else {
            if (i === 0) {
                alert("1st object in array is not number, will skip...");
            } 
            else if (i === 1) {
                alert("2nd object in array is not number, will skip...");
            }  
            else if (i === 2){
                alert("3rd object in array is not number, will skip...");
            }    
            else {
                alert((i+1).toString() + "th object in array is not number, will skip...");
            }
        } 
    }
    return result;
}

for 循环会添加此i ++一会儿循环，使代码更加清晰。

无需在主代码中声明 i ：）

The for loop adds this i++ You make in a while loop and makes code a bit more clear.
No need for declaring i in main code :)

1. 始终使函数简化主代码。
   


2. 使即使有人想破坏逻辑也不会出错的函数。

1. Always make functions to simplify main code.
   
2. Make function that will never make mistake even if somebody wants to break The logic.

虽然不要让学校放假，但您的创造力却很棒！ ：）

Although don't make school break Your creativity, Your code is great! :)

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