C / C++ / MFC

Overriding function main()?

8-Mar-01 18:05

If you have a variable to the button

CRect rc;
m_myButton.GetWindowRect(&rc);

otherwise

CRect rc;
GetDlgItem(IDC_MYBUTTON)->GetWindowRect(&rc);

I believe this comes in co-ordinates relative to the dialog, in which case ClientToScreen will five you screen co-ords. If I am wrong, ScreenToClient gives you client co-ords.

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

Jason Gerard8-Mar-01 14:47

8-Mar-01 14:47

Ok. I'm a VB/(wannabe Java/C#) programmer so don't flame me. I'm in a C++ class in college and my professor gave the class an odd assignment. I have no clue where to begin. Here is the problem:
Given the program:

#include <iostream.h>
main () {
cout<<” Hello, World\n”;
}

Modify it to produce the output:
Initialize
Hello, World
Clean up

Do not change main () in any way.

Now this is blowing my mind. Confused | :confused:

He said there was a way to override the main function but I do not see how. Any help would be greatly appreciated. Thanks. Smile | :)

MCSD, MCSE

Michael Dunn8-Mar-01 15:58

Michael Dunn

8-Mar-01 15:58

You don't overload (that's the term, not override) main(), you just write it. Hmmm | :|

THe way I'd do it is make a class with a constructor that prints "Initialize" and a destructor that prints "Clean up" and declare a global variable of that class. Globals are constructed before main() is called, and destructed after it returns.

--Mike--
http://home.inreach.com/mdunn/
I'm finger-lickin' good!

Jason Gerard8-Mar-01 16:59

8-Mar-01 16:59

I meant overload, I'm always interchanging them by accident. Anyway, my teacher's English is not very good and I posted this during class. I talked with him and a few students and we all misunderstood him. Apparently, he wants us to somehow derive from ostream or streambuf and overload operator<< for cout. Not quite sure how but that is what he said. Thanks for the help.

However, I tried your approach but the destructor is never called.

Here is the output:

Initialize
Hello, World
Press any key to continue

Here are some code snippets:

//MyClass.h

class MyClass
{
public:
MyClass();
~MyClass();

};

//MyClass.cpp

MyClass::MyClass()
{cout << "Initialize\n";}

MyClass::~MyClass()
{cout << "Clean up\n";}

// test.cpp

#include <iostream>
#include "MyClass.h"
using namespace std;
MyClass myClass = MyClass();
int main()
{
cout << "Hello, World\n";
return 0;
}

MCSD, MCSE

Christian Graus8-Mar-01 17:16

8-Mar-01 17:16

I was in the process of coming up with a similar response when I saw Michaels reply, so I jumped into VC to give it a try, and the following

#include <iostream.h>

class MyClass
{
public:
MyClass() {cout << "Initialize\n";};

~MyClass() {cout << "Clean up\n";};
};

MyClass myClass = MyClass();

int main()
{
cout << "Hello, World\n";
return 0;
}

worked fine for me. I don't believe myClass needs to be defined, but I left it that way ;0)

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

Christian Graus8-Mar-01 17:16

8-Mar-01 17:16

I was in the process of coming up with a similar response when I saw Michaels reply, so I jumped into VC to give it a try, and the following

#include <iostream.h>

class MyClass
{
public:
MyClass() {cout << "Initialize\n";};

~MyClass() {cout << "Clean up\n";};
};

MyClass myClass = MyClass();

int main()
{
cout << "Hello, World\n";
return 0;
}

worked fine for me. I don't believe myClass needs to be defined, but I left it that way ;0) I noticed you had a .cpp file for MyClass, but it did not include MyClass.h ??

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

Jason Gerard9-Mar-01 13:44

9-Mar-01 13:44

It does have an include, I just didn't paste it it. I copied your example exactly, added the missing include for iostream, and compiled. I came across something quit odd.

When I compile the app using:

#include <iostream>
using namespace std;

The destructor for myClass is never executed.

However, when I use:

#include <iostream.h>

with the namespace line removed, the destructor fires.

Anyone have a clue as to why?

MCSD, MCSE

Christian Graus9-Mar-01 22:35

9-Mar-01 22:35

Funny enough, I couldn't get a compile at all using namespace std, so I took it out. I have a question. Of what use is

#include

by itself ?

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

l a u r e n10-Mar-01 2:49

l a u r e n

10-Mar-01 2:49

#include (according to the strict definition) causes the preprocessor to insert the named file where the #include directive is found as if it were typed there by the coder

my thoughts:
if the name following the directive is blank the preporcessor will either ignore the directive (smart move) or try to include the filename "" (dumb move as this would cause an error file-not-found) ... so actually i guess it ignores the directive

heh

---
"every year we invent better idiot proof systems and every year they invent better idiots"

Christian Graus10-Mar-01 12:33

10-Mar-01 12:33

That's about what I thought it would do, it appears the iostream include ( which I put in myself ) was actually what that line did in the original posters code...

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

Jason Gerard10-Mar-01 5:21

10-Mar-01 5:21

Nothing.. I had <iostream> after the #include. However, I wasn't using the HTML escape sequence for < and > like I am now so <iostream> is being interpreted as an HTML tag and not being displayed. Actually, codeproject is removing them. It occured in your posts also. Use & lt; for < and & gt; for >. Be sure to remove the space between the & and the other characters.

Also, to use using namespace std, you have to remove the .h from iostream. Don't know why but that is how it works for me.

MCSD, MCSE

Christian Graus10-Mar-01 12:37