Shrinking An Array After Creation

Sage
Posts: 1,066
Joined: 2004.07
Post: #16
When I originally posted, it was while developing my mesh class where some models could have 5000 vertices and others only 20. I wanted to be able to get rid of those extra 4980 vertices (each containing three floats) to free up memory in the computer. I'm getting into BlitzMax more now so I may just use that where I can use slices to shrink arrays like this:
Code:
myArray = myArray[..myArray.length-1]
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Member
Posts: 198
Joined: 2005.01
Post: #17
Your mesh class could also have had this:

std::vector<Vertex> vertices;

On init you could specify the exact number of vertices you'd need, or you could max it out to begin with:

vertices.resize(5000);

And when you want to chop off the extras:

vertices.resize(vertices.size() - 1);

STL is hella nice. Smile

(disclaimer: that's all off the top of my head, I think the method names are right...)

Cryptic Allusion Games / Cryptic Allusion, LLC
http://www.cagames.com/
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Sage
Posts: 1,199
Joined: 2004.10
Post: #18
Allow me to second STL. If you're writing in C++ and aren't using STL, you're wasting your time, and are probably creating more subtle bugs than you can shake a stick at.
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Member
Posts: 208
Joined: 2005.04
Post: #19
OneSadCookie Wrote:I think you mean "much less memory-efficient than arrays".

I mean that if you know you're going to have somewhere between 0 and 10000 items, and you end up with only 100 items, a linked list will have a smaller memory footprint than an array of length 10000.
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Luminary
Posts: 5,143
Joined: 2002.04
Post: #20
That's certainly true, but if you want an array with somewhere between 0 and 10000 items the last thing you would do would be allocate space for 10000 and waste 99% of it.

As others have pointed out, C++ provides std::vector, but doing something in C with realloc is dead easy too.
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