Thread: Another question on classes

That default constructor seems odd to me...

Maybe something like:

Code:

public:
matrix();

then

Code:

matrix::matrix()
{
r=10;
c=10;
v=0;
}

then you can define other constructors if the user specifies values
im not exactly sure how your method would work...if it works

try changing the .h file so that the matrix constructor has no arguments ( matrix() )

edit:: oh i also mean change the cpp file to what i said before as well

JaWib didn't follow the thread very carefully, and he doesn't appear to understand your assignment, and anyways the constuctor is fine. Your constructor has default parameter values, so it plays a dual role. It serves as a constructor that takes three int parameters, and it also serves as a default constructor: if you call the constructor with no arguments, the default values will be used.

However, the whole issue with your constructor that you've failed to address is that a constructor is used to initialize the data members of your class. Your constructor was declared to accept three parameters of type int, yet your class doesn't have three data members of type int. So, there appears to be some kind of discrepancy.

"I had already picked up a couple other books prior to the suggested ones... one of them is an Ivor Horton book, but it's the "Beginning Visual C++ 6"

I don't know if your class is going to be covering Visual C++, and if it's not, I would exchange Beginng Visual C++ for Beginning C++, which is a more comprehensive text on C++. However, they are both good books, and I have them both. The first 12 chapters of Beginning Visual C++ is a condensed version of Beginning C++, so it's more cursory.

Visual C++ is both a compiler and a method for Windows programming. You can study C++ and use Visual C++ as your compiler, but never get into Windows Programming with Visual C++, which involves using the Microsoft Foundation Classes(MFC) to create Windows as the means of interacting with the user of your program. For instance, a lot of people don't like MFC, and don't use it for Windows Programming--they use the Windows API directly. I think "Beginning C++" is a much better C++ reference than "Beginning Visual C++", but either one is undoubtedly much better than your current text.

The default constructor is the following:
Matrix(int r=10, int c=10, int v=0);

Not really. That is a constructor that takes 0, 1, 2, or 3 arguments, but no matter how many arguments you send to the function it ALWAYS has three parameters--or values--that presumably you will do something with in the body of the constructor.

If you define your constructor like this:

Matrix::Matrix(int r, int c, int v){

}

then why would you declare it with any parameters? Since you aren't doing anything with the values you would declare the constructor like this:

Matrix();

and define it like this:

Matrix::Matrix()
{
}

I am supposed to handle this if that is the case, because we are supposed to use the interface provided in the book

Exactly. So, that's a big hint your definition of the constructor is totally wrong, and until you get that straightened out, there's no use proceeding. The parameters of your constructor probably have something to do with the data member:

IntList *Values;

What's an IntList?