No == operator found while comparing structs in C++

Question

Comparing two instances of the following struct, I receive an error:

struct MyStruct1 {
    MyStruct1(const MyStruct2 &_my_struct_2, const int _an_int =          


        

Answer 1

Starting in C++20, it should be possible to add a full set of default comparison operators (==, <=, etc.) to a class by declaring a default three-way comparison operator ("spaceship" operator), like this:

struct Point {
    int x;
    int y;
    auto operator<=>(const Point&) const = default;
};

With a compliant C++20 compiler, adding that line to MyStruct1 and MyStruct2 may be enough to allow equality comparisons, assuming the definition of MyStruct2 is compatible.