C++ unordered_set create

#include <iostream>
#include <unordered_set>

using namespace std;

int main()/*from w  ww .  j  av a2s  .c o  m*/
{
    unordered_set<string> Colors;

    Colors.insert("Red");
    Colors.insert("Green");
    Colors.insert("Blue");

    if(Colors.find("Red")!= Colors.end())
        cout << "Found Red!" << endl;
    else
        cout << "Red Missing!" << endl;

    auto ReturnValue = Colors.emplace("Red");
    if(!ReturnValue.second)
        cout << "Red is Already in Set!" << endl;
    else
        cout << "Red Added to Set!" << endl;

    cout << "There are " << Colors.count("Red")
        << " Red entries." << endl;

    ReturnValue = Colors.emplace("Orange");
    if(!ReturnValue.second)
        cout << "Orange is Already in Set!" << endl;
    else
        cout << "Orange Added to Set!" << endl;

    Colors.erase("Red");

    if(Colors.find("Red")!= Colors.end())
        cout << "Found Red!" << endl;
    else
        cout << "Red Missing!" << endl;

    return 0;
}