為什么會導致無限循環？

Question

我正在測試選擇排序，但不斷收到infite循環。

當我有一切都很好

while(arr.length > 3)

但是，當我將其降低或更改為應有的水平時，則會在代碼中造成無限循環。

while(arr.length > 2)

這是我其余的代碼：

  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

您需要在每個循環條目中重置smallest值，否則，一旦刪除11 ，其他值將與之進行比較，並且index永不變（ 3 ）； 一旦index大於數組的長度（第二次迭代），就不再拼接數組。

 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)