二分查找c++简单模板

//数组a[]中有n各元素，已经按升序排序，待查找的元素x
sort(a,a+n); //升序排序
template<class Type>
int BinarySearch(Type a[],const Type&x,int n)
{
    int left=0; //左边界
    int right=n-1; //右边界
    while(left<=right)
    {
        int middle=(left+right)/2; //中点
        if(x==a[middle])return middle; //找到x，返回数组中的位置
        if(x>a[middle]) left=middle+1;
        else right=middle-1;
    }
    return -1; //未找到x
}





#include<iostream>
#include<algorithm>
using namespace std;
bool compare(int a,int b)
{
    return a<b;                       //升序
}
template<class Type>int BinarySearch(Type a[],const Type&x,int n)
{
    int left=0;
    int right=n-1;
    while(left<=right)
    {
        int middle=(left+right)/2;
        if(a[middle]==x) return middle;
        if(a[middle]<x) left=middle+1;
        else right=middle-1;
    }
    return -1;
}
int main()
{
    int a[20];
    int n,m;
    cin>>n;
    for(int i=0; i<n; i++)
    {
        cin>>a[i];
    }
    sort(a,a+n,compare);
    for(int i=0; i<n; i++)
    {
        cout<<a[i]<<" ";
    }
    cout<<endl;
    m=BinarySearch(a,234,n);
    cout<<m<<endl;
    return 0;
}