Hi Devs,
So i made this c++ project ,which is an array that allocates itself automatically so you can use it without defining its size and it works with all types
here is the GitHub repository if you're interested ,please star it so more people can see it :
GitHub - unknown989/cxx-dynamic-array: This is a Header-Only Dynamic Allocated Array Library for C++
So how does this differ from std::vector or std::array ?
I see your readme has "If you wanna use type std::string it won't work , so instead use char*"
Does that go for anything else which isn't PoD ?
IE, anything with a non-trivial constructor.
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Well in std::array yoy have to set a size with the ability to update it.Originally Posted by Salem
and it is the same as std::vector.
It was intended to be a C project not a Cpp but i switched to cpp
Well, I'd say that it is good that you're learning how to write a generic dynamic array class template from scratch, but you might want to do some reading on how to write classes that do resource management and what std::vector provides and why.
For example, one obvious problem is that your Array does memory management, but you only implemented the default constructor and destructor: what happens should an Array get copied?
A legitimate concern might be: how do I modify an element within an Array? Both the operator[] and the get member functions return by value.
Another problem with your Array is that appending to it is slow: you only reallocate for one new element each time. The append also can unnecessarily result in two copies of the original object because you use a value parameter and then don't use move assignment within the append... although I'm not sure if copying/moving is going to work in the first place because normally we would use placement new as you only have memory allocated rather than a constructed object in the destination location.
Last edited by laserlight; 05-08-2021 at 06:45 PM.
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Hi, thanks for your feedback.
i noticed that it is slow while appending compared to std::vector, it's 2-3 times slower.
and for the allocation,it re-allocates itself if it expects an element size that is bigger than the current size of the array.
I'm planning to make it equivalent to std::vector or close at least and why not better,i haven't gave it too much time,bcz it's just something i did to learn memory allocation in c++.if you got any tips on how to make it faster,tell me.
This looks pretty problematic:
My guess is that this goes back to my observation that within append you're assigning to an object that has not been constructed. You should look into the use of placement new to create and place the new object in the allocated memory, and then into the use of an explicit destructor call to destroy the object when you pop (and also to destroy any remaining objects when the Array is destroyed).If you wanna use type std::string it won't work , so instead use char*
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