折半查找

//折半查找
//author：https://blog.csdn.net/qq_31828515/article/details/51791833
//date:2020.4.23
#include <cstdio>
using namespace std;

int binary_research(int arr[],int left,int right,int element)
{
    while(left<=right)
    {
        int mid = (left+right)/2;
        if(arr[mid]>element)
        {
            right = mid - 1;
        }
        else if(arr[mid]<element)
        {
            left = mid + 1;
        }
        else
        {
            return mid;
        }
    }
    return -1;
}

int main()
{
    int array[] = {1,2,3,4,5,6,7,8,9};
    int right = 8;
    int left = 0;//定义右下标并初始化为0
    int element = 0;//定义查找的元素并初始化为0
    printf("请输入要查找的元素：");
    scanf("%d",&element);
    int location = binary_research(array,left,right,element);
    if(location>=0)
        printf("The element's location is %d\n",location);
    else
        printf("Don't exit this element.\n");
    return 0;
}