二分查找

/********************************
* 程序名称：二分查找
* 开发时间：2021-01-19
*******************************/
#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;
int s[10001];    /*数组*/

//search
int BinarySearch(int n, int s[], int x) {
    int low = 0, high = n-1, middle;
    while(low <= high) {
        middle = (low + high) / 2;
        if (s[middle]== x) {
            return middle;       //找到返回Middle 
        } else if(s[middle] > x) {
            high = middle - 1;    //左边 
        } else { 
            low = middle + 1;     //右边 
        }
    }
    
    return -1;    // none
} 
//main() star
int main() {
    //code here 
    int n, x;
    cin >> n >> x;
    for(int i =0; i<n; i++) {
        cin >> s[i];
    }
    sort(s, s + n);     //排序 
    for(int i =0; i<n; i++) {
        cout << s[i] <<" ";
    }
    
    int exist = BinarySearch(n, s, x);
    
    cout << exist << endl;   //输出查找结果 
    
    return 0;
}

测试：
输入数据：

6 5
1 7 9 6 5 2
1 2 5 6 7 9
2

--------------------------------
Process exited after 9.959 seconds with return value 0
请按任意键继续. . .

输出数据：

2