我試圖理解為什么我的代碼的一個(gè)版本有效，而另一個(gè)版本不起作用。我已經(jīng)全局定義了var數(shù)，所以我想如果我運(yùn)行函數(shù)sumArray（），那么它會(huì)傳入元素，但它總是返回0。只有當(dāng)我再次定義它更接近函數(shù)sumArray（）時(shí)，它才正確計(jì)算。將變量編號(hào)用于 printReverse（） 函數(shù)是否會(huì)禁止在 sumArray（） 中再次使用它？如果您注釋掉，那么您將在控制臺(tái)中看到它返回0。var numbers = [2, 2, 3];var numbers = [1, 2, 3];var result = 0;function printReverse() {  var reversed = [];  while (numbers.length) {    //push the element that's removed/popped from the array into the reversed variable    reversed.push(numbers.pop());  }  //stop the function   return reversed;}//print the results of the function printReverse()console.log(printReverse());var numbers = [2, 2, 3];function sumArray() {  //pass each element from the array into the function  numbers.forEach(function(value) {    //calculate the sum of var result + the value passed through and store the sum in var result    result += value;  });  //return and print the sum  return result;}//print the results of the function sumArray()console.log(sumArray());