为什么会导致无限循环？

Question

我正在测试选择排序，但不断收到infite循环。

当我有一切都很好

while(arr.length > 3)

但是，当我将其降低或更改为应有的水平时，则会在代码中造成无限循环。

while(arr.length > 2)

这是我其余的代码：

  let arr = [55,21,33,11,25] let newArr = []; let smallest = 999999999; let index; function selectionSort() { while(arr.length > 2) { //loops through the numbers array for(i = 0; i < arr.length; i ++) { // if the item is smaller, than pass it through if(arr[i] < smallest) { //change smallest to the arr[i] smallest = arr[i] index = i; } } //remove the smallest number from the arr arr.splice(index, 1) //push the smallest number to the new arr newArr.push(smallest) } } selectionSort() 

Answer 1

您需要在每个循环条目中重置smallest值，否则，一旦删除11 ，其他值将与之进行比较，并且index永不变（ 3 ）； 一旦index大于数组的长度（第二次迭代），就不再拼接数组。

 let arr = [55, 21, 33, 11, 25] let newArr = []; let index; function selectionSort() { while (arr.length > 2) { let smallest = Infinity; //loops through the numbers array for (i = 0; i < arr.length; i++) { // if the item is smaller, than pass it through if (arr[i] < smallest) { //change smallest to the arr[i] smallest = arr[i] index = i; } } //remove the smallest number from the arr arr.splice(index, 1) //push the smallest number to the new arr newArr.push(smallest) } } selectionSort() console.log(newArr, arr)