I come from C# so having to manually manage memory is new to me.

I was wondering what happens if I have a class Foo that holds another object Bar and I instantiate foo on the heap; where does bar end up?

In code:

class Bar {
	
	public:
		Bar(){}
};

class Foo {

	Foo()
	 : bar() 
	{

	}

	private:
		Bar bar;
};

int main()
{
	Foo* foo = new Foo();

	delete foo;

	return 0;
}

Is bar also placed on the heap? and in that case do I need to manually release bar or is it freed automatically by Foo?

The bar variable is a part of the Foo class, contained within it (Foo's memory allocation is big enough to contain this Bar instance inside itself -- sizeof(Foo) >= sizeof(Bar)).

Wherever a Foo is allocated, then m_bar is created inside that allocation. When a Foo is constructed, the m_bar variable is also constructed automatically. Likewise, when a Foo is destructed, the m_bar variable is also automatically destructed.

m_bar never needs to be free'd/deleted, because it was not created using malloc/new.

Those are both good explanations, thanks a lot for helping me clear this out guys :)