lang/spacecompat.cpp

The following code example is taken from the book
C++20 - The Complete Guide by Nicolai M. Josuttis, Leanpub, 2021
The code is licensed under a Creative Commons Attribution 4.0 International License.

---

// raw code

#include <iostream>

class MyType {
private:
  int value;
public:
  MyType(int i)    // implicit constructor from int:
   : value{i} {
  }

  bool operator==(const MyType& rhs) const {
    return value == rhs.value;
  }
};

bool operator==(int i, const MyType& t) {
  return t == i;   // OK with C++17
}

int main()
{
  MyType x = 42;
  if (0 == x) {
    std::cout << "'0 == MyType{42}' works\n";
  }
}