二分查找

//二分查找
#include<bits/stdc++.h>
using namespace std;

int n;
int binary_search(int a[],int x)
{
    int low,high;
    int mid;
    low = 1;
    high = n;
    while(low<=high)
    {
        mid=(low+high)/2;
        if(a[mid]==x)
        {
            return mid;
        }
        else if(a[mid]>x)
        {
            high=mid-1;
        }
        else low=mid+1;
    }
    return 0;
}
int main()
{
    int a[1000];
    cout<<"input the size of the array:\t";
    cin>>n;
    int i,j,k;
    int x;
    cout<<"input the elements:"<<endl;
    for(i=1;i<=n;i++)
        cin>>a[i];
    cout<<"input the number what you want to find in the array:\t";
    cin>>x;
    int is_find;
    is_find=binary_search(a,x);
    if(is_find)
        printf("find it at the index of %d in the array\n",is_find);
       else
        cout<<"not found"<<endl;
}