8.17


#include<iostream>

using namespace std;

template<typename T>

class Add_3

{

public:

Add_3(T a,T b,T c)

{

x=a;

y=b;

z=c;

}

T sum()

{

return x+y+z;

}

private:

T x,y,z;

};

int main()

{

Add_3<int> sum3_1(1,2,3);

Add_3<float> sum3_2(1.1,2.2,3.3);

Add_3<double> sum3_3(1.11,2.22,3.33);

cout<<"三个整数之和："<<sum3_1.sum()<<endl;

cout<<"三个单精度之和："<<sum3_2.sum()<<endl;

cout<<"三个双精度之和："<<sum3_3.sum()<<endl;

return 0;

}