#include <map>
#include <iostream>
 
int main()
{
    const std::map<int, const char*> m{
        { 0, "zero" },
        { 1, "one" },
        { 2, "two" },
    };
 
    {
        auto p = m.equal_range(1);
        for (auto& q = p.first; q != p.second; ++q) {
            std::cout << "m[" << q->first << "] = " << q->second << '\n';
        }
 
        if (p.second == m.find(2)) {
            std::cout << "end of equal_range (p.second) is one-past p.first\n";
        } else {
            std::cout << "unexpected; p.second expected to be one-past p.first\n";
        }
    }
 
    {
        auto pp = m.equal_range(-1);
        if (pp.first == m.begin()) {
            std::cout << "pp.first is iterator to first not-less than -1\n";
        } else {
            std::cout << "unexpected pp.first\n";
        }
 
        if (pp.second == m.begin()) {
            std::cout << "pp.second is iterator to first element greater-than -1\n";
        } else {
            std::cout << "unexpected pp.second\n";
        }
    }
 
    {
        auto ppp = m.equal_range(3);
        if (ppp.first == m.end()) {
            std::cout << "ppp.first is iterator to first not-less than 3\n";
        } else {
            std::cout << "unexpected ppp.first\n";
        }
 
        if (ppp.second == m.end()) {
            std::cout << "ppp.second is iterator to first element greater-than 3\n";
        } else {
            std::cout << "unexpected ppp.second\n";
        }
    }
}