[求助]面向对象程序设计

#include <cstddef>

template<typename T, std::size_t N>
struct fuck
{
    T data_[N];
   

    T sum( void ) const
    {
        T sum = T();
        for( size_t i=0; i!=N; ++i )
            sum += data_[i];
        return sum;
    }
    T avg( void ) const
    {
        return sum()/N;
    }
};


#include <iostream>

int main( void )
{
    fuck<double,4> a = { 1.1, 2.2, 3.3, 4.4 };
   

    std::cout << a.sum() << '\n'
              << a.avg() << std::endl;
            

    return 0;
}