Class object member of another class

[Metallon]

I have a fairly simple class, and I want objects of another class to be private members of that class, and objects of that class are initialized with a value through its constructor like so:

class MyClass {
public:
  //whatever code...
private:
  OtherClass objectA("Metallon", 10);
};

//Constructor of OtherClass
OtherClass::OtherClass(std::string aString, int anInt)
:myString(aString), myInt(anInt) {}

The four errors I get are actually two errors repeated twice: "error:expected identifier before string constant" and "expected ',' or '...' before string constant".

What am I doing wrong?

[Zhuge]

Don't call the constructor inside of the MyClass definition. Use an initializer list inside MyClass's default constructor.

[PanGalactic]

You need to initialize objectA in the member initialization list of MyClass's constructors, not inline as you have done on line 5.

[Metallon]

Alright, that works, and actually makes more sense. Is it just how it is? You can't call constructors inside a class declaration?

PanGalactic: you mention an initialization list. If I wanted to create multiple objects with MyClass's default constructor, wouldn't it be fine to do this:

MyClass::MyClass() {
  OtherClass objectA("Hello", 1), objectB("World", 2);
}

[Zhuge]

No because the objectA inside of MyClass has already been constructed at that point. If anything, you would just be creating a local variable that hides the objectA in the class.

[Metallon]

Could you show me an example, please?

[Zhuge]

Like this?

MyClass::MyClass() : objectA("Hello", 1), objectB("World", 2) {
}

You already seemed to be using initializer lists in OtherClass. It's the same thing.

[Metallon]

So I just put objectA, objectB etc. in the MyClass private members' part? And then do like what you showed me there?

Wait... ok haha I get it. You create the objects once, and then initialize it. Because that's what a constructor would do, initialize its members. I know this. Wow, a little embarassing, but yes, you're right.

Thank you for your help! =)