8.17

#include<iostream>
using namespace std;
template<typename G>
class Sum{
public:
Sum(T a,T b,T c)
{ x=a; y=b; z=c;
}
G add()
{ return x+y+z;
}
private:
G x,y,z;
};
int main()
{ Sum<int> s1(3,6,9);
Sum<double> s2(11.11,22.22,33.33);
cout<<"三个整数的和为:"<<s1. add()<<endl;
cout<<"三个双精度数的和为:"<<s2.add()<<endl;
return 0;