Expression preceding parentheses of apparent call must have (pointer-to-) function type

Question

Problem :

I am very new to C++ and trying to learning C++ template. Please find below my code, I am trying to define a template class and also want to call the member function in the main() method..

template <typename T>

class Calculate {

    T _x;

    T _y;

    Calculate () {};

public

    Calculate (T x, T y) :_x(x), _y(y) {};

    T add const() { return _x + _y; };

    T sub const() { return _x - _y; };

};

int main() {

    Calculate <int> ar(7,8);

    cout << ar.add() << endl;

}

But whenever I try to build this program, I am getting following error at the last line of above code :

Expression preceding parentheses of apparent call must have (pointer-to-) function type

How can I resolve this issue?

Answer 1

·   You need to add required header inclusion and using keywords

·    Also add : after public

·    Please move const to proper position

#include <iostream>

using std::cout;

using std::endl;

template <typename T>

class Calculate {

    T _x;

    T _y;

    Calculate () {};

public:

    Calculate (T x, T y) :_x(x), _y(y) {};

    T add() const { return _x + _y; };

    T sub() const { return _x - _y; };

};

int main() {

    Calculate <int> ar(7,8);

    cout << ar.add() << endl;

}