concept.cpp

/*
 * Concepts Example:
 */

#include <iostream>

using namespace std;

template<typename T>
concept bool Addable = requires(T a, T b) {
    { a+b } -> T;
};

template<typename T>
concept bool Subtractable = requires(T a, T b) {
    { a-b } -> T;
};

template<typename T>
concept bool AddableAndSubtractable = Addable<T> && Subtractable<T>;

AddableAndSubtractable myFunction(AddableAndSubtractable a, AddableAndSubtractable b) {
    return a + b;
}

Addable myAdd(Addable a, Addable b) {
    return a + b;
}

class Add {
    int x;
public:
    Add(int x) : x(x) {}
    Add operator+(Add a) { return *this; }
};

int main() {
    cout << myFunction(1,2) << endl;
    cout << "0x" << hex << myFunction(0xfff, 0xabc) << endl;

    Add a(1);
    Add b(1);

    Add d = myAdd(a, b);

    return 0;
}