emplace

template<class... _Valty>
    void emplace_back(_Valty&&... _Val)
    {   // insert by moving into element at end
    if (this->_Mylast == this->_Myend)
        _Reserve(1);
    _Orphan_range(this->_Mylast, this->_Mylast);
    this->_Getal().construct(this->_Mylast,
        _STD forward<_Valty>(_Val)...);
    ++this->_Mylast;
    }