二分查找模板

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int a[1001];
int n;
int binsearch (int g[],int m)
{
int l=1;
int r=n;
int mid;
while (l<r)
{
mid=(l+r)/2;
if (a[mid]==m) return mid;
else if (a[mid]>m) r=mid-1;
else if (a[mid]<m) l=mid+1;
}
}
int main ()
{
cin>>n;
for (int i=1;i<=n;i++)
cin>>a[i];
int m;
cin>>m;
cout<<binsearch(a,m);
return 0;
}