explicit vector(const A& al = A());
explicit vector(size_type n, const T& v = T(), const A& al = A());
vector(const vector& x);
vector(const_iterator first, const_iterator last,
    const A& al = A());All constructors store the allocator object al (or, for the copy constructor, x.get_allocator()) in allocator and 
initialize the controlled sequence. The first constructor specifies an empty initial controlled sequence. The second 
constructor specifies a repetition of n elements of value x. The third constructor specifies a copy of the sequence 
controlled by x. The last constructor specifies the sequence [first, last).
In this implementation, if a translator does not support member template functions, the template:
template<class InIt>
    vector(InIt first, InIt last, const A& al = A());is replaced by:
vector(const_iterator first, const_iterator last,
    const A& al = A());All constructors copy N elements and perform no interim reallocation.