8.17建立一个类模板实现求3个数之和

#include<iostream>using namespace std;template<typename T>class sum{private:T x,y,z;public:sum(T a,T b,T c){x=a;y=b;z=c;}T add(){return x+y+z;}void print(){cout<<x<<" "<<y<<" "<<z<<endl;}};int main(){sum<int> s1(1,2,3);sum<double> s2(1.1,2.2,3.3);cout<<"三个整数分别为："<<endl;s1.print();cout<<"三个整数之和为："<<s1.add()<<endl;    cout<<"三个双精度整数分别为:"<<endl;s2.print();cout<<"三个双精度整数之和为:"<<s2.add()<<endl;return 0;}