implementation of Vector (using C++)

  The Vector will be a first-class type,meaning that unlike the primitive array in C++,the Vector can be cpoied,and the memory it uses can be automatically reclaimed(via its destructor).

  First,recall some important fetures of C++ primitive arrays:

    (1):The array is simply a pointer variable to a block of memory;the autual array size must be

maintained separately by the programmer.

    (2):The block of memory can be allocated via new[],but then must be free via delete[].

    (3):The block of memory can not be resize

 

  Now,outline the main details of Vector:

well,go to read the source code,it's very simple ^_^

#include <iostream> template <typename T> class Vector { int Size,Capacity; //vector's size and capacity T* array; public: const static int SPARE_CAPACITY = 20; //we can see iterator and const_iterator are simply other names for a //pointer variable... typedef T* iterator; typedef const T* const_iterator; iterator Begin() {return &array[0]; } const_iterator Begin()const {return &array[0]; } iterator End() {return &array[Size]; } const_iterator End()const {return &array[Size]; } public: explicit Vector (int size=0) : Size(size),Capacity(size+SPARE_CAPACITY) { array = new T[Capacity]; } Vector(const Vector& rhs) : array(NULL) {operator=(rhs); } ~Vector() {delete[] array; } const Vector& operator=(const Vector& rhs) { if (this != &rhs) { delete[] array; Size = rhs.Size; Capacity = rhs.Capacity; array = new T[Capacity]; for (int k=0;k<Size;k++) array[k] = rhs.array[k]; } return *this; } void ReSize(int newSize) //change the size of the vector { if (newSize > Capacity) Reserve(newSize*2 + 1); Size = newSize; } void Reserve(int newCapacity) //change the capacity of the vector { if (newCapacity < Size) return ; T *oldArray = array; array = new T[newCapacity]; for (int k=0;k<Size;k++) array[k] = oldArray[k]; Capacity = newCapacity; delete[] oldArray; } T& operator[](int index) {return array[index]; } const T& operator[](int index)const {return array[index]; } bool empty()const {return size() == 0; } int size()const { return Size; } int capacity()const {return Capacity; } void Push_back(const T& x) { if (Size == Capacity) Reserve(2*Capacity + 1); array[Size++] = x; } void Pop_back() {Size--; } };