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vb style arrays in c++

fireking · 2002-09-12T12:31:35

ok, i know visual basic sucks (unless you are making a really GUI enhanced program, such as a map editor or something), but if it has any good features, its gotta be the way arrays are handled. Ok in vb, here is a quick run down of how arrays are treated Public Whatever() as string this is a dynamic array, it has no size, cuz we dont know how big its going to be Redim Whatever(5) we just made the array have 6 parts Whatever(0) = "Yeah" Whatever(1) = "Uh huh" Whatever(2) = "Wowers!" Whatever(3) = "Coolio" Whatever(4) = "Yippy" Whatever(5) = "HOLY CRAP" Redim Preserve Whatever(4) we just made the array have 5 parts, and the preserve keywords lets us keep the memory of all the other parts we didnt get rid of, and we got rid of part 5 Redim Whatever(4) we just made the array hvae 5 parts, but we didnt preserve anything so it got completely erased, and now its 5 empty strings in the array Here is a common use that makes vb arrays so cool Public Type item name as string id as integer End Type Public Items() as item Public Sub AddItem(i as item) Redim Preserve Items(Ubound(Items)+1) //ubound gets the upper bound of the array Items(Ubound(Items)) = i //ubound is now 1 more than it was before, cuz we added one, we set this to i End Sub Public Sub RemoveItem(name as string) Dim del as integer Dim i as integer For i = 0 to Ubound(Items) If Items(i).name = name then //if we found the name del = i //this is the place we want to start at Exit For End If Next For i = del to Ubound(Items)-1 //start at the place, and iterate Items(i) = Items(i+1) //set this item to the next one Next Redim Preserve Items(Ubound(Items)-1) //delete the last one End Sub So as you can see, i want to accomplish this same thing in C++. Also, I have not found a way to determine the UBOUND of an array in C++. The C++ equivalent of this would just be the number of parts in the array minus 1, because C++ doesnt let you start from 1 to 10, or 5 to 43 like vb does. C++ always starts at 0. So the upperbound would just be the number of parts minus 1. Any help will rock, thanks, --Fireking Owner/Leader Genetics 3rd Dimension Development

General and Gameplay Programming Programming

Started by fireking September 11, 2002 09:00 PM

20 comments, last by fireking 21 years, 7 months ago

Oluseyi

2,123

September 12, 2002 01:46 AM

quote:Original post by fireking
there are other memory functions, but i didnt read up on them..

please explain why i should not use them in C++? where is the concern?

It is good practice to advocate the use of C++ features exclusively (at least until you know better) when using a C++ compiler because of better interoperation of the features. The Standard C Library memory management functions do not know about the behaviors of classes (and structs; they''re functionally near-equivalent, only difference is inheritance/access specification), meaning they do not call constructors or destructors and other such nuances. The Standard C++ operators new and delete are not only aware of C++ features, but are user-extensible and fully support all C memory operations. That''s just one of the instances where modern C++ features are to be preferred.

Prefer std::string over null-terminated character strings.
Prefer std::vector over type *, dynamically allocated arrays.

Naturally, there are times when the right-hand constructs are logically equivalent - and occasionally even superior - but they are relatively few.

daerid

354

September 12, 2002 12:31 PM

What you need to realize, fireking, is that VB does a TON of shit for you (meaning you don''t have to worry about it).

About the only thing that c++ does for you is maintain the program stack.

That''s it. Everything else, you''re on your own. That means that you have to explicitly tell your program exactly what you want it to do 99% of the time.

Now, you can simplify that by using C++ features, such as classes, templates, operator overloading, etc.. but the fact remains that you have to explicitly define the behavior somewhere before it can be used.

You''re a lot safer in C++ if you just basically assume that you (the programmer) have to tell the language what to do, throughout the entirety of the program.

daerid@gmail.com

vb style arrays in c++

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