stl类vector

template<class T>class std::vector { public: vector(); //Default constructor //Precondition :None; //Postcondition :An empty vector exists. vector(size_type n); //Creates a vector with n elements //Precondition :None; //Postcondition :A vector of n elements exists bool empty()const; //Detemines whether the vector is empty //Precondition :None; //Postcondition :Return true if the vector is empty //otherwise returns false size_type size()const; //Detemines the length of the vector //the return type size_type is an integral type //Precondition :None; //Postcondition :returns the number of the items that //are currenty in the vector void push_back(const T &) //Inserts a new element at the end of the vector. //precondition :none //postcondition :the new element is the last element //in vector void pop_back(); //removes the last element of the vector //Precondition :there is at least one element in the //vector //postcondition :the last element of the vector is removed iterator insert(interator i,const T &); //Insert an item into the vector //before the element specified by the iterator //Precondition :the iterator is initialized //postcondition :Item val is inserted into the vector //and an iterator to the newly inserted item is return iterator erase(iterator i); //remove element at i //precondition : the iterator must be initialized //postcondition :returns the iterators to the item //following the removed item void clear(); //Erases all the elements in the vector //precondition :NOne; //postcondition :the vector has no elements iterator begin(); //returns an iterator to the first item in the vector //precondition :None; //postcondition :if the vector is empty //the value returned by the end() is returned iterator end(); //returns an iterator to test for the end of //the vector //precondition :None; //Postcondition :the value for the end of the vector //was returned };