sort a map by Value

[NajaR12]

Hi all, Can anybody tell me how to sort a map based on the values. e.g. Map[key1] = box3; Map[key2] = box1; Map[key3] = box4; Map[key4] = box2; i want result like, Map[key2] = box1; Map[key4] = box2; Map[key1] = box3; Map[key3] = box4; thanks in advance, RKR

[Chandrasekharan P]

AFAIK, You can sort maps only by the Key element. I think that is the the point of having maps. Your scenario might work out some way. but what if 2 different keys has the same values? how will you sort it?

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[Roger Stoltz]

NajaR12 wrote:

Can anybody tell me how to sort a map based on the values.

Why do you want to do that? Your desire suggests that you have misunderstood the purpose of a map. The key is supposed to be unique and the value is identified by its corresponding key so you may write code such as in order to retrieve the "box" associated with the key:

Box& box = Map[key];

However, if your "boxes" are unique you may use them as keys, e.g.:

Map[box1] = key2;
Map[box2] = key4;
Map[box3] = key1;
Map[box4] = key3;

Consider using a std::list that is entry-sorted.

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[Chris Losinger]

a map isn't really the right container for this. if you have pairs that need to be sorted, why not put them into a vector/list of std::pair<key,box> and sort that on box ?

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