Get the first empty key in map<int, TValue>

LocateFirstEmptySlotInMap.cpp

#include <iostream>
#include <map>


template<typename  TValue>
int locateFirstAvailableSlot(std::map<int, TValue> my_map)
{
    typename std::map<int, TValue>::iterator it;
    int expected_value=1;
    for ( it = my_map.begin(); it != my_map.end(); it++ )
    {
        if(it->first == expected_value)
        {
            expected_value++;
        }
        else
        {
            return expected_value;   
        }
    }
    return expected_value;
}
int main()
{
    std::map<int, std::string> series;
    series.insert ( std::pair<int,std::string>(100, "ok") );
    std::cout<<"Expectedvalue: 1, ActualValue: "<< locateFirstAvailableSlot(series)<<std::endl;
    
    std::map<int, std::string> series2;
    std::cout<<"Expectedvalue: 1, ActualValue: "<< locateFirstAvailableSlot(series2)<<std::endl;
    
    std::map<int, std::string> series3;
    series3.insert ( std::pair<int,std::string>(1, "First") );
    series3.insert ( std::pair<int,std::string>(2, "Second") );
    series3.insert ( std::pair<int,std::string>(4, "Forth") );
    std::cout<<"Expectedvalue: 3, ActualValue: "<< locateFirstAvailableSlot(series3)<<std::endl;
    
    std::map<int, char> series4;
    series4.insert ( std::pair<int,char>(1, 'a') );
    series4.insert ( std::pair<int,char>(2, 'b') );
    std::cout<<"Expectedvalue: 3, ActualValue: "<< locateFirstAvailableSlot(series4)<<std::endl;

    return 0;
}