C++ Incomplete class type pointer

Question

In a source file I have 2 class definitions

class Foo
{
public:
    int * GetPtr(){
        return Obj;
    }

    int * Obj;
}

class Bar
{
public:
    ...

    std::vector<Foo> FooVector;
}

And in the same source file I have this function

void DoSomething()
{
    Bar* barVar = CreateBar(); // Returns pointer to class object
    Foo* fooVar = &barVar->FooVector[0]; 

    if (fooVar->GetPtr()) // Error here
        ...
}

Trying to compile this, I get the error "Pointer to incomplete class type not allowed" but the class is defined a few lines above it.

Answer 1

我通过正确实现类来解决这个问题。