Question

i have an STL map ;
i would like to get the first non NULL value in the map;
is there an efficient/quick way to do that?

Answer 1

#include <map>
#include <algorithm>
#include <iostream>

using namespace std;

bool IsNotNull(const pair<const int, int>& i)
{
        return i.second != 0;
}

int main() {

        map<int, int> m;
        m[0] = 0;
        m[1] = 1;
        map<int, int>::const_iterator it = find_if(m.begin(), m.end(), IsNotNull);
        cout << it->second << endl;
        return 0;

}

Ideone demo