How to get position of a certain element in strings vector, to use it as an index in ints vector?

Question

I am trying to get the index of an element in a vector of strings, to use it as an index in another vector of int type, is this possible ?

Answer 1

Nobody mentioned the general version as a function for any std::vector so here it is (in one ugly line) :

#include 

template  long long int indexOf(const std::vector &vector , const T &data){

   return (std::find(vector.begin(), vector.end(), data) != vector.end()) //Is it in the vector ?
           ?
           std::distance(vector.begin(), std::find(vector.begin(), vector.end(), data)) //Yes, take the distance (C++11 and above, see the previous answers)
           : -1; //No, return -1
}

And without the ternary operator :

#include 

template  long long int indexOf(const std::vector &vector , const T &data){

     if((std::find(vector.begin(), vector.end(), data) != vector.end())){
         return std::distance(vector.begin(), std::find(vector.begin(), vector.end(), data));
     }
     else{return -1;}
}

It returns either the index or -1 if the element is not in the vector.

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Note that this may be very slow for big vectors, as it computes two times std::find.