Comments on: 10.3 — Aggregation

By: STommY

STommY — Wed, 16 Jul 2008 22:03:39 +0000

I’m not sure whether the statement above will call the constructor you defined, as the signatures do not match, and so the default constructor will be called.

By: Stuart

Stuart — Fri, 11 Jul 2008 10:52:56 +0000

Duh, it seems obvious now. LOL.

Thanks. ;D

By: Alex

Alex — Fri, 11 Jul 2008 02:13:36 +0000

It’s assigned NULL as a default parameter just in case the programmer wants to create a department with no teacher. For example:

Department cDept;

In this case cDept would call the Department constructor with pcTeacher set to NULL. This NULL value would then be assigned to cDept.m_pcTeacher by the constructor.

By: Stuart

Stuart — Thu, 10 Jul 2008 21:37:09 +0000

Alex, I don’t understand why the pointer pcTeacher is assigned NULL as a Department constructor parameter, because it assigns to the address of the pTeacher pointer when an object of Department is instantiated. It seems like it’s never a null pointer. (?)

By: Learn C++ - » 10.2 — Composition

Learn C++ - » 10.2 — Composition — Mon, 05 May 2008 02:14:29 +0000

[...] Posts « A.5 — Debugging your program (watching variables and the call stack) | Home | 10.3 — Aggregation » Tuesday, December 4th, 2007 at 2:55 [...]

By: Alex

Alex — Thu, 10 Apr 2008 01:56:09 +0000

Yep. It’s just another class defined somewhere else. Probably in another header that’s included by Department.cpp.

Edit: I went ahead and defined a Teacher class just above the Department class so people can compile the example if they want.

By: Tom

Tom — Wed, 09 Apr 2008 18:39:29 +0000

typo: “When cDept is destroyed, the m_pcTeacher pointer is destroyed”

Where does the Teacher variable type get declared? Anywhere outside the aggregate class?

By: Alex

Alex — Sun, 30 Mar 2008 18:28:33 +0000

It’s really personal preference how you do your hungarian notation. When it comes to pointers (or references), I use p (or r), then the letter denoting the type of the class, then the variable name. Thus, a pointer to a class would be prefixed pc. But however you decide to proceed is up to you (or your company). Just be consistent.

By: Chris Buck

Chris Buck — Sun, 30 Mar 2008 08:03:40 +0000

Could you pls elaborate on what’s the difference between pcTeacher and pTeacher as far as hungarian notation is concerned?
Wasn’t the ‘c’ used to clarify that it’s an instance of a class and didn’t we omit it when it’s a pointer to a class?

Like shouldn’t the ‘c’ be omitted in both cases and both pointers just be named pTeacher?

By: Learn C++ - » 10.4 -- Container classes

Learn C++ - » 10.4 -- Container classes — Thu, 31 Jan 2008 02:04:03 +0000

[...] Alex: Fixed. [...]