二分查找的两种方式

/*
 * query.cpp
 *
 *  Created on: 2013年8月4日
 *      Author: Administrator
 */


#include <iostream>

using namespace std;

class Person{
	string name;
	int age;
	string salary;

public:
	Person(string name , int age , string salary):name(name),age(age),salary(salary){

	}
	friend bool operator<(const Person& a , const Person& b ){
		return a.name < b.name;
	}

	friend bool operator==(const Person& a ,const Person& b){

		return a.name == b.name;
	}

	friend ostream& operator<<(ostream& o , const Person& a){
		o<<"name"<<" : "<<a.name << " salary: "<<a.salary;

		return o;
	}
        //以下是递归调用的方式
	friend Person* binarysearch(Person* p , int n , string name){

		if( n == 0 ){
			return NULL;
		}

		int mid = n/2;
		Person a(name,0,"");
		if(p[mid] == a){
			return p + mid;
		}else if( a < p[mid] ){
			return binarysearch(p,mid,name);
		}else{
			return binarysearch(p+mid+1,n - mid - 1,name);
		}

	}

	friend Person* binarysearch1(Person* p , int n , string name){
		cout<<"这时使用非递归版的二分查找"<<endl;

		int l = 0;
		int r = n - 1;
		Person t(name,0,"");
		while( l <=  r){
			int mid = (l+r)/2;

			if(p[mid] == t){
				return p + mid;
			}else if( t < p[mid]  ){
				r = mid - 1;
			}else{
				l = mid + 1;
			}
		}

		return NULL;
	}
};
int main(){

	Person persons[3]={
			Person("allen",21,"40000"),
			Person("bllen",22,"41000"),
			Person("cllen",23,"42000")
	};

	cout<<"请输入您要查找的人的名字:";
	string name ;
	cin >> name;

	Person* p = binarysearch1(persons,3,name);

	if(p == NULL){
		cout<< "没有找到"<<endl;
	}else{
		cout<< *p <<endl;
	}
}