C++ return structure from method

Question

I would like to return a structure from a method but the returned structure needs to be used in a different class. That is my current code:

Song.h:

class song{   
  public:
    Song(char szTitle[50]);
    Song();
    struct ToneStruct;
    ToneStruct GetNextNote();
    ~Song();
};

Song.cpp:

struct ToneStruct {
    char cTone;
    int iTime;
    int iTimePassed;
};

ToneStruct Song::GetNextNote(){
while (iTempTime != endOfFile) {
//do stuff
    while (iTempTime != 59) {
        //do stuff
    }
    ToneStruct toneStruct(cTone,iPlayTime, iTimePassed);
    return toneStruct;
}
ToneStruct endStruct('X', 0, 0);
return endStruct;
}

Because of the method I get an error saying "declaration is incompatible with song.h" and on the structs inside the method it says "incomplete type is not allowed". What am I doing wrong?

Answer 1

You have forward declared struct ToneStruct inside the song class, which means it is inside the song namespace and is thus accessible as song::TongStruct, but you declared a ToneStruct structure in the source file outside the song namespace, which will then be assessible as ToneStruct. The compiler will see them as different types.

To fix the error, you should either move the forward declaration out of the class or use the Song::ToneStruct for your type.