Question

I would like to search within a vector<std::pair<int, vector<int> > >. This won’t work due to the vector parameters:

std::vector<std::pair<int, std::vector<int> > > myVec;
iterator = find(myVec.begin(), myVec.end(), i);

Search would be on the first std::pair template parameter (int), in order to get the vector associated with it.

Answer 1

You could make do with the following (pretty ugly) functoid:

struct FindFirst {
    FindFirst(int i) : toFind(i) { }
    int toFind;
    bool operator() 
        ( const std::pair<int, std::vector<int> > &p ) {
            return p.first==toFind;
    }
};

using it like this ( I couldn’t get bind2nd to work – that’s why I used the c’tor ):

int valueToFind = 4;
std::find_if(myVec.begin(), myVec.end(), FindFirst(valueToFind));

---

I think what you would like is a map:

std::map< int, vector< int > > foo;

You can then add elements, search by key etc:

int key = 4; //This will be the key
vector<int> value(5, 4); //Fill some values (5 4's in this case) into the vector

foo[key]=value; //Adds the pair to the map. Alternatively;
foo.insert( make_pair(key, value) ); //Does the same thing (in this context)

Looking at the way you’ve done things though, you might be wanting a std::multimap (which allows multiple values to have the same key) Class docs here