Iterating over an STL map

  • Thread starter Thread starter Bob Altman
  • Start date Start date
B

Bob Altman

Hi all,

I read somewhere that the STL map class stores entries internally sorted by the
key. I wrote a small test program (below) that verifies that iterating through
the map returns entries with ascending key values. My question is: Is this
guaranteed behavior or is it just the current implementation which might change
in the future?

TIA - Bob

--- Code example ---

#include "stdafx.h"
#include <map>
#include <iostream>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
map<int, string> myMap;

myMap[2] = "2";
myMap[5] = "5";
myMap[1] = "1";
myMap[3] = "3";
myMap[6] = "6";

for (map<int, string>::iterator it = myMap.begin();
it != myMap.end(); it++)
{
cout << it->first << " : " << it->second.c_str() << endl;
}

return 0;
}
 
Bob said:
Hi all,

I read somewhere that the STL map class stores entries internally sorted by the
key. I wrote a small test program (below) that verifies that iterating through
the map returns entries with ascending key values. My question is: Is this
guaranteed behavior or is it just the current implementation which might change
in the future?
Click to expand...

Bob:

It is guaranteed.
 
I read somewhere that the STL map class stores entries internally sorted by the
key. I wrote a small test program (below) that verifies that iterating through
the map returns entries with ascending key values. My question is: Is this
guaranteed behavior or is it just the current implementation which might change
in the future?
Click to expand...

I'd expect it to be guaranteed.

The sorting is done by the traits object - and defaults to less<Key>,
but if need be you can always specify your own.

Dave
 
David Lowndes said:
I'd expect it to be guaranteed.

The sorting is done by the traits object - and defaults to less<Key>,
but if need be you can always specify your own.

Dave
Click to expand...

Many thanks to both Davids! - Bob
 
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