二元搜索算法（分治法）

#include<iostream>
using namespace std;


int Binary_search(int *a, int p, int r, int x)
{
    if (p > r)
        return false;
    int midpoint = (p + r) / 2;
    if (a[midpoint] == x)
        return midpoint+1;
    else if (x < a[midpoint])
        Binary_search(a, p, midpoint - 1, x);
    else Binary_search(a, midpoint + 1,r, x);
}



void main()
{
    int a[10];
    for (int i = 0; i < 10; i++)
        cin >> a[i];
    cout<<Binary_search(a, 0, 9, 5);
}