二分查找(分治)

对N个整数进行查找，获取给出的数在该组数据中的位置

#include<stdio.h>
int binary_search(int Array[],int N,int num);
int main()
{
    int Array[1000]={0};
    int N,k,index;
    int i;
    scanf("%d",&N);
    for(i=0;i<N;i++)
        scanf("%d",&Array[i]);

    /////排序(从小到大)
    //selection_sort(Array,N);

    scanf("%d",&k);//升序数组Array[]中二分搜索
    index=binary_search(Array,N,k);
        printf("这是第%d个数\n",index+1);

    return 0;
}

int binary_search(int Array[],int N,int num)//二分查找
{
    int low,high,mid;
    low=0;
    high=N-1;   
    while(low<=high)
    {
         mid=(low+high)/2;
         if(Array[mid]==num)
             return mid;
         else if(Array[mid]>num)
             high=mid-1;
         else low=mid+1;
    }
    return -2;//没在该组数据中会输出-1
}