Re: Re: New Book: The School of Niklaus Wirth

"Orlando Llanes" <ollanes@pobox.com> wrote in message
> I also have to disagree here. C++ has its quirks, but when
> comparing C++ to OO Pascal, one of my pet peeves is that Pascal does
> not call its constructor or destructor automatically (it's incredibly
> annoying that your virtual functions cause a program crash because
> they were not initialized). Also, why on Earth would anyone want
> multiple constructors or multiple destructors? Generally speaking,
> Pascal is strict on type checking which does not allow for
> overloading. One more Pascal pet peeve, why is there no unsigned
> integer (one of my biggest pet peeves)?
>


Why would anyone want multiple constructors? I would think that there are
plenty of reasons.
I know that I use them repeatedly. Multiple constructors are ways of
specifying classes for certain situations,
especially if the language doesn't support somethin like c++'s template
facility. Let's say that I create a class to read disc files
and memory-mapped files. With multiple constructors, I have the option of
something like as follows:
(c++ notation)
        char* filename = file1.txt;
        CFileReader* reader = new CFileReader(filename); //this would create
and instance the reader for files.
        reader->Read();


        CMemoryMappedFile* memfile = new CMemoryMappedFile;
        CFileReader *memreader = new CFileReader(memfile); // create instance
of reader for memorymapped files
        memreader->Read();


This is code reuse. I used the same class for performing the same function
on varying types of data, and the best part is,
I only need to learn one interface. Overloading is a wonderful feature and
I would be hard pressed to use a language that
doesn't support.


Jean

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