emplace_back in vector (Xcode)

I am trying to learn the new features in C++11. And I am testing the following code in XCode.

class CClass
{
    std::string s;
public:
    CClass()
    {
        cout<<"Default Constructor"<<endl;
    }
    CClass(const std::string v) :s(v) {
        cout<<"Constructor"<<endl;
    }

    CClass(const CClass& other): s(other.s) {
        cout<<"Copy Constructor"<<endl;
    }
    CClass(CClass&& a) noexcept
    {
        cout<<"Move Constructor"<<endl;
        s = std::move(a.s);
    }
    CClass& operator = (const CClass& other)noexcept
    {
        cout<<"Copy Assignment"<<endl;
        if(this != &other)
        {
            s = other.s;
        }
        return *this;
    }
    CClass& operator = (CClass&& other) noexcept
    {
        cout<<"Move Assignment"<<endl;
        if(this != &other)
        {
            s = std::move(other.s);
        }
        return *this;
    }
    void Print()
    {
        cout<<s<<endl;
    }
};

void test()
{
    std::vector<CClass> v;
    CClass x("hello");
    //CClass y("buffallo");
    //v.push_back(x);
    cout<<"--------------------"<<endl;
    v.emplace_back("uiuiu");
    cout<<"--------------------"<<endl;
    for(int i = 0; i < v.size(); i++)
    {
        v[i].Print();
    }
}

When I uncomment the push back I get the following result:

Constructor
Copy Constructor
--------------------
Constructor
Move Constructor
--------------------
hello
uiuiu

Otherwise, if I comment it, I get:

Constructor
--------------------
Constructor
--------------------
uiuiu

My question is why is move constructor not being called in second case. It is only being called in the first case when vector is initially not empty.