数据结构：二分查找法

#include <iostream>
#include<string>
#include<ctime>

#include<cstdlib>
#include<algorithm>
using namespace std;
//非递归版本的二分查找法
int BinarySearch1(int a[],int n,int key){
    int low=0;
    int high=n-1;
    int mid;
    if(key<a[0]||key>a[n-1])
        return -1;
    while(low<=high)
    {
        mid=(low+high)/2;
        if(key==a[mid]){
            cout<<"查找成功，mid="<<mid<<endl;
            return mid;
        }
        if(key<a[mid])
            high=mid-1;
        else  //key>a[mid]  应该到mid+1 ......high区间去找
            low=mid+1;
    }
    if(low>high){
        cout<<"查找失败"<<endl;
        return -1;
    }
}

int main(){
    int *a;
    int i=0;
    int n,m;
    int key;
    a=new int[n];
    cout<<"请输入n:"<<endl;
    cin>>n;
    srand((unsigned)time(NULL));
    for(i=0;i<n;i++){
        m=rand()%100+1;
        a[i]=m;
    }
    sort(a,a+n);
    cout<<"长度是"<<n<<"的有序数据列表："<<endl;
    for(i=0;i<n;i++)
        cout<<a[i]<<" ";
    cout<<endl;
    cout<<"输入你要找的key:"<<endl;
    cin>>key;
    cout<<BinarySearch1(a,n,key);
    }