Sorting a STL list? - GameCreators Forum

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McLaine

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Posted: 7th Feb 2012 15:51

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I understand that STL Lists have a built in sort function.

However, If my list is of this example struct:

struct Player
{
string name;
int score;
}

What would be the best way to sort the list based on score?

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WLGfx

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Posted: 7th Feb 2012 19:50

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If you're using a vector then it's a simple as any old sort function.

+ Code Snippet

psuedo code:

vector<Player> scores;
...
for (int loop=0; loop<scores.size()+1, loop++)
{
    if (scores[loop].score<scores[loop+1])
    {
        Player temp;
        temp.name = scores[loop].name;
        temp.score = scores[loop+1].score;
        scores[loop].name = scores[loop+1].name;
        scores[loop].score = scores[loop+1].score;
        scores[loop+1].name = temp.name;
        scores[loop+1].score = temp.score;
    }
}

EDIT: Nah that's wrong... Sowwy man... Needs a second loop inside... But it gives you an idea...

Mental arithmetic? Me? (That's for computers) I can't subtract a fart from a plate of beans!
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Matty H

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Posted: 7th Feb 2012 20:20

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Have you looked here:
list::sort

Seems you write your own 'compare' function which will take two of your objects and return true or false. It's up to you what attribute you use to compare, 'score' in your case.

I only looked at it briefly but I have done compare functions in Java, I am presuming this is the same, but I may be wrong.

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Dar13

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Posted: 7th Feb 2012 23:56

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What MattyH told is exactly what you do. You create a function that compares two given instances of that struct and return either true or false depending on which one is greater than the other.

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McLaine

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Posted: 8th Feb 2012 01:49 Edited at: 8th Feb 2012 01:57

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Cheers for the effort WLGfx, I got what you were getting at. That's a standard bubble sort which I was going to fall back on. It's not far from the actual implementation, but I was looking to use the in built sort method as I assume that's going to be faster.

@Matty H and Dar13
Coolio, thanks for the link. I tried to find that in the C++ manual but failed, I have no idea why. Maybe I was just looking at the top level of list.

So, build a method that takes two parameters of the type of my struct, and that returns true or false. Then pass that method name to the sort method?

Nice one fellas!