类模板（P339）

#include<iostream>
#include<string>
using namespace std;

template<class T1,class T2>
class Pair
{
public:
T1 first;
T2 second;
Pair(T1 k,T2 v):first(k),second(v){}
bool operator<(const Pair<T1,T2>&p)const;
};

template<class T1,class T2>
bool Pair<T1,T2>::operator<(const Pair<T1,T2>&p)const
{
return first<p.first;
}

int main()
{
Pair<string,int>student1("Tom",19);
Pair<string,int>student2("Jim",21);
Pair<int,int>coordinate(10,20);
Pair<string,string>dic("word","单词");
cout<<"学生:"<<student1.first<<""<<student1.second<<endl;
cout<<"学生:"<<student2.first<<""<<student2.second<<endl;
cout<<"坐标:"<<coordinate.first<<""<<coordinate.second<<endl;
cout<<"字典顶:"<<dic.first<<""<<dic.second<<endl;
bool a =student1<student2;
if(a == 0) cout<<student1.first<<"位于"<<student2.first<<"之后"<<endl;
else cout <<student1.first<<"位于"<<student2.first<<"之前"<<endl;
return 0;
}