Basic question on new and delete

[yop]

...you may want to reuse the code as part of some bigger framework and if you don't notice that missing delete (which is very likely to happen), you'll end up with a memory leaking process.

Think that you mght have an application that runs for several hours and that the memory is allocated meny times without freeing it, eventually your memory resources will run out and your app will remind you a very popular OS back in '95

[Codepoet]

Another good reason for delete is that you may have, at another place, a memory leak. If you use a memory debugger to find these you will get much less warnings this way.

[rh]

Or simply create all your objects as value types (ala RAII) and just let them die of natural causes when they're out of scope. After all, pointers are SO yesterday

[yop]

After all, pointers are SO yesterday

I'm sooo with you. If you can avoid them you save yourself a lot of troubles

[Codepoet]

Or simply create all your objects as value types (ala RAII) and just let them die of natural causes when they're out of scope. After all, pointers are SO yesterday

That's a very bad idea: In another thread somebody did that:

for(int i = 0; i < 5; ++i)
{
   QThreadDerivedClass t;
   t.start();
}

for(int i = 0; i < 5; ++i)
{
   QThreadDerivedClass t;
   t.start();
}

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Just after starting the thread the instance will be destructed because it went out of scope. You need pointers to avoid some very ugly code. Maybe use them through something like boost::shared_ptr with automatic reference counting, it's even exception safe.

[yop]

...because it went out of scope...

This was an implementation bug What would you prefer in the following situation?

MyModalDialog modalDlg;
modalDlg.exec()
if(modalDialog.getSomething()==true){
//do something;
}

MyModalDialog modalDlg;
modalDlg.exec()
if(modalDialog.getSomething()==true){
//do something;
}

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or

MyModalDialog *modalDlg = new MyModalDialog;
modalDlg->exec()
if(modalDialog->getSomething()==true){
//do something
}
delete modalDlg;

MyModalDialog *modalDlg = new MyModalDialog;
modalDlg->exec()
if(modalDialog->getSomething()==true){
//do something
}
delete modalDlg;

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Then after code being added by many others...

MyModalDialog *modalDlg = new MyModalDialog;
modalDlg->exec()
if(modalDialog->getSomething()==true){
//do something
}else{
return; //Ouch
}
// Lot's of code that might also return somewhere
delete modalDlg;

MyModalDialog *modalDlg = new MyModalDialog;
modalDlg->exec()
if(modalDialog->getSomething()==true){
//do something
}else{
return; //Ouch
}
// Lot's of code that might also return somewhere
delete modalDlg;

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I'm not saying don't use pointers, but why not avoid them whem they are not needed?

[Codepoet]

@yop: I cited not you but rh
Yes one can (should?) avoid them if possible: Your example perfectly demonstrates it. It gets even worse when you work with exceptions.
I never meant not using instances on the stack, that's most of the time ok but not always.

[rh]

The only real restriction to RAII-style initialized variables that i've encountered is, to state the obvious, that its type must be known at compile-time. Anything with runtime attributes (such as factory classes, etc.) still require pointers.

My biggest qualm on using pointers? That damn "->" operator! C++ is *supposed* to be a language of type reduction, yet the arrow operator is 3x the keystrokes (don't forget the shift) as other dot-notated languages.

If this makes me shallow (also i like ladies with big boobies), then so be it but in my opinion, RAII initialized variables are not only easier on the carpal tunnel, but are inherently safer (like GC without the overhead) and should be used whenever possible.

I realize this is drifting slightly from the original post. If everyone is happy with me having the last word i'm good with that