Vector的实现

#include <cassert>

 
template <class object>
class Vector {
public:
    explicit Vector(int initsize = 0)
        : _size(initsize), _capacity(initsize + SPARE_CAPACITY)
            {_object = new object[_capacity];}
    Vector(const Vector &rhs) : _object(NULL) 
        { operator=(rhs);}
    ~Vector()
        {delete [] _object;}
        
    const Vector& operator=(const Vector &rhs)
    {
        if(this != &rhs)
            {
                delete [] _object;
                _size = rhs._size;
                _capacity = rhs._capacity;
                
                _object = new object[_capacity];
                for(int k = 0; k < _size; k++)
                    _object[k] = rhs._object[k];    
            }
            return *this;
    }
    
    void resize(int newSize)
    {
        if(newSize > _capacity)
            reserve(newSize * 2 + 1);
        _size = newSize;
    }
    
    void reserve(int newCapacity)
    {
        if(newCapacity < _size)
            return;
        
        object *oldobject = _object;
        _object = new object[newCapacity];
        for (int n=0; n<_size; n++)
            _object[n] = oldobject[n];
        delete [] oldobject;
        _capacity = newCapacity;
    }
    
    object& operator[](const int index)
    {
        assert(index >= 0 && index < _size);
        return _object[index];
    }
    
    const object& operator[](const int index) const
    {
        assert(index >= 0 && index < _size);
        return _object[index];
    }
    
    bool empty() const 
    {return _size == 0;}
    
    int size() const 
    {return _size;}
    
    int capacity() const 
    {return _capacity;}
    
    void push_back(const object &x)
    {
        if(_size == _capacity)
            reserve(2*_capacity + 1);
        _object[_size++] = x;
    }
    
    void pop_back()
        {_size--;}
    
    const object& back() const 
        { return _object[_size - 1];}
    
    typedef object* iterator ;
    typedef const object* const_iterator;
    
    iterator begin()
    {return &_object[0];}
    
    iterator end()
    {return     &_object[_size];}

    const_iterator begin() const
    {return &_object[0];}
    
    const_iterator end() const
    {return &_object[_size];}    

    enum{ SPARE_CAPACITY = 16};    
private:
    int _size;
    int _capacity;
    object *_object;    
};

// output
// sizeof(vint) is: 12
// size of vint is: 24
// capacity of vint is: 27
// size of vint2 is: 48
// capacity of vint2 is: 97
// the last element of vint is: 23
// the 5 element of vint is: 4
// 012345678910111213141516171819202122
// [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22]
// [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 1330118777 1380205901 1027954249 1207974467 1346719055 1028150337 1702057308 1247572850 2037214569 1129270272 1346456641 1413563472 977485121 1702057308 1247572850 2037214569 1886404956 1635017028 1668238428 1275096161 1313818447 1448232275 1547522629 1296648796]
// [Finished in 0.9s]
#include <iostream>
#include "printCollection.h"
#include "c2_vector.h"
using namespace std;
int main()
{
    //default constructor
    Vector<int> vint;
    Vector<int> vint2;
    
    //calc class size, two int, one pointer, so size is 12
    cout <<"sizeof(vint) is: " << sizeof(vint) << endl;
    
    //void push_back(const object &x)
    for (int n=0; n<24; n++)
    {
        vint.push_back(n);
    }
    
    //const Vector& operator=(const Vector &rhs)
    vint2 = vint;
    
    //void resize( int newSize)
    vint2.resize(48);
    
    //int size(); int capacity();
    cout << "size of vint is: " << vint.size() << endl;
    cout << "capacity of vint is: " << vint.capacity() << endl;
    cout << "size of vint2 is: " << vint2.size() << endl;
    cout << "capacity of vint2 is: " << vint2.capacity() << endl;
    
    //const object& back();
    cout << "the last element of vint is: " << vint.back() << endl;
    
    //object& operator[](const int index)
    cout << "the 5 element of vint is: " << vint[4] << endl;
    
    //void pop_back()
    vint.pop_back();
    
    //typedef object* iterator; typedef const ojbect* const_iterator
    //iterator begin(); iterator end();
    for (Vector<int>::iterator iter = vint.begin(); iter != vint.end(); iter++)
    {
        cout << *iter;
    }
    cout << endl;
    
    printCollection(vint); 
    printCollection(vint2); 
}

// output
// sizeof(vint) is: 12
// size of vint is: 24
// capacity of vint is: 27
// size of vint2 is: 48
// capacity of vint2 is: 97
// the last element of vint is: 23
// the 5 element of vint is: 4
// 012345678910111213141516171819202122
// [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22]
// [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 1330118777 1380205901 1027954249 1207974467 1346719055 1028150337 1702057308 1247572850 2037214569 1129270272 1346456641 1413563472 977485121 1702057308 1247572850 2037214569 1886404956 1635017028 1668238428 1275096161 1313818447 1448232275 1547522629 1296648796]
// [Finished in 0.9s]
#include <iostream>
#include "printCollection.h"
#include "c2_vector.h"
using namespace std;
int main()
{
    //default constructor
    Vector<int> vint;
    Vector<int> vint2;
    
    //calc class size, two int, one pointer, so size is 12
    cout <<"sizeof(vint) is: " << sizeof(vint) << endl;
    
    //void push_back(const object &x)
    for (int n=0; n<24; n++)
    {
        vint.push_back(n);
    }
    
    //const Vector& operator=(const Vector &rhs)
    vint2 = vint;
    
    //void resize( int newSize)
    vint2.resize(48);
    
    //int size(); int capacity();
    cout << "size of vint is: " << vint.size() << endl;
    cout << "capacity of vint is: " << vint.capacity() << endl;
    cout << "size of vint2 is: " << vint2.size() << endl;
    cout << "capacity of vint2 is: " << vint2.capacity() << endl;
    
    //const object& back();
    cout << "the last element of vint is: " << vint.back() << endl;
    
    //object& operator[](const int index)
    cout << "the 5 element of vint is: " << vint[4] << endl;
    
    //void pop_back()
    vint.pop_back();
    
    //typedef object* iterator; typedef const ojbect* const_iterator
    //iterator begin(); iterator end();
    for (Vector<int>::iterator iter = vint.begin(); iter != vint.end(); iter++)
    {
        cout << *iter;
    }
    cout << endl;
    
    printCollection(vint); 
    printCollection(vint2); 
}