C++ make_pair map find second

Question

I have a map like this (both of first and second parameters are unique):

std::map<DWORD, DWORD> mapTest;
mapTest.insert(make_pair(1, 101));
mapTest.insert(make_pair(2, 102));
mapTest.insert(make_pair(3, 103));

And I have a searcher, which is work perfectly for the first values of the map:

bool SearchInMap(DWORD firstmap, DWORD * secondmap)
{
    if (mapTest.end() == mapTest.find(firstmap))
        return false;

    *secondmap = mapTest[firstmap];
    return true;
}

But I need another method, which could search in the second parameters and looks like what I showed. If possible I don't want to use for or while cycles. As I know I probably need a find_if search, but I can't handle it.

Thanks in advance you're help!

Possible duplicate of [Find mapped value of map](https://stackoverflow.com/questions/4263640/find-mapped-value-of-map) — Paul Varghese, Jun 01 '18 at 23:04
@PaulVarghese Thanks, it's working! But can we do it with find or find_if or something like this? — Gregori, Jun 01 '18 at 23:28
@Gregori 이원용's answer on that duplicate shows a possible example of `find_if` — kmdreko, Jun 01 '18 at 23:29

Pavan Chandaka · Answer 1 · 2018-06-02T00:13:45.313

1

You can do it in simple way using lambdas.

DWORD val = 103;
auto result = std::find_if(stMap.begin(), stMap.end(), [val](const auto& mo) {return mo.second == val; });

DWORD foundkey = result->first;

The important thing is capturing your input

[val]

edited Jun 02 '18 at 00:13

answered Jun 02 '18 at 00:01

Pavan Chandaka

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I forgot say I'm using vs 2008 for some reason, and this method won't work on that. Btw thank you, and i'm glad if you can make for 2008 vs. – Gregori Jun 02 '18 at 15:55

C++ make_pair map find second

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