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

You need to explicitly define operator == for MyStruct1.

struct MyStruct1 {
  bool operator == (const MyStruct1 &rhs) const
  { /* your logic for comparision between "*this" and "rhs" */ }
};

Now the == comparison is legal for 2 such objects.

Answer 2

Because you did not write a comparison operator for your struct. The compiler does not generate it for you, so if you want comparison, you have to write it yourself.