程序由Golang实现，代码如下：
1.使用递归实现二分查找
//使用递归进行二分查找func binarySearchTest() {//二分查找的数组必须是已经排好序的nums := []int{1, 3, 5, 6, 7, 10, 12, 15, 17, 18, 19, 20, 21}value := 2var index int = searchIndex(nums, value)fmt.Println("index:", index)}//在nums中查找元素value，返回indexfunc searchIndex(nums []int, value int) int {return searchIndexInArea(nums, value, 0, len(nums)-1)}//在nums中查找元素value，，返回index. 其中index位于[left,right]之间func searchIndexInArea(nums []int, value int, left int, right int) int {if left > right {return -1}mid := left + (right-left)/2if nums[mid] < value {return searchIndexInArea(nums, value, mid+1, right)} else if nums[mid] > value {return searchIndexInArea(nums, value, left, mid-1)}return mid}2.使用循环实现二分查找
func searchIndex2(nums []int, value int) int {left, right := 0, len(nums)-1for left <= right {mid := left + (right-left)/2if nums[mid] < value {left = mid + 1} else if nums[mid] > value {right = mid – 1} else {return mid}}return -1}
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