Class Interactions

Contains - by value.

class X

{

private Y itsY;

};

!! indicates that X and Y have
identical lifetimes.

When X is destroyed, Y will be destroyed too

Uses.

class X

{

public: void F(const Y&);

};

Y is used within the source code
of class X.

Have different lifeline. Y may outlive X.

Contains - by reference.

class X

{

private:

Y* itsY;

};

This is used to indicate that X
and Y have dissimilar lifetimes.

Y may outlive X.

Inheritance.

Class Y:X

{}

This indicates that Y is a public

base class of X. have same lifetime.

Invoking a member function.

void X::F(Y& theY)

{

P p;

V v = theY.M(p);

}

Using a container class.

class X

{

private:

Set<Y*> itsYs;

};

Contains array or so.

Can have different lifetimes