Very nice Template, just tried it and works great.
then one same value for different key.
andre wrote:
Hi,
anybody can advise how to get a key from the map having value only?
The other way around its easy of course, and map is supposed to be used
like that.
But I need to find a key for a given value.
thanks
This sohould do it:
//--------------------------------------
#include <iostream>
#include <map>
#include <utility>
#include <string>
template<typename T1, typename T2>
struct BySecond
{
BySecond(const T2& t): t_(t)
{
}
bool operator()(const std::pair<T1, T2>& p) const
{
return p.second == t_;
}
private:
T2 t_;
};
int main()
{
std::map<int, std::string> m;
m[0] = "Null";
m[1] = "Eins";
m[2] = "Zwei";
std::map<int, std::string>::iterator it =
find_if(m.begin(), m.end(), BySecond<int, std::string>("Zwei"));
if (it!= m.end())
std::cout << "Found it: " << it->first << " : " << it->second <<
std::endl;
return 0;
}
//--------------------------------------
HTH
Stefan
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