数据结构One_Vector(向量的简单实现)

Posted 2020-08-05 豆子

  1 #include <iostream>
  2 using namespace std;
  3 
  4 template<typename Object>
  5 class  Vector
  6 {
  7 private:
  8     int theSize;                         //实际数据大小
  9     int theCapacity;                     //实际容器容量大小
 10     Object *objects;                     //基本数组
 11 public:
 12     enum { SPACE_CAPACITY = 16 };        //默认容量大小
 13     
 14     explicit Vector(int initSize = 0)    //单参数构造函数要用explicit()避免类型在后台转换
 15         : theSize(initSize), theCapacity(initSize + SPACE_CAPACITY) {
 16         objects = new Object[theCapacity];
 17     }
 18     Vector(const Vector& rhs) : objects(NULL) {    //复制构造函数--调用operator=对已有的Vector进行复制
 19         operator = (rhs);
 20     }
 21     ~Vector() {
 22         delete[] objects;
 23     }
 24 
 25     const Vector& operator = (const Vector& rhs) //重载赋值运算符
 26     {
 27         if (this != &rhs)                        //避免复制自身--混淆检验
 28         {
 29             delete []objects;                    //删除旧的内存空间
 30             theSize = rhs.size();                //生成同样的样本大小
 31             theCapacity = rhs.theCapacity;       //生成同样的容量大小
 32 
 33             objects = new Object[capacity()];    //生成与所复制的Vector同样容量的新数组
 34             for (int k = 0; k < size(); k++)
 35                 objects[k] = rhs.objects[k]; 
 36         }
 37         return *this;
 38     }
 39     
 40     void resize(int newSize)
 41     {
 42         if (newSize > theCapacity)        //重置大小
 43             reserve(newSize * 2 + 1);     //新大小
 44         theSize = newSize;
 45     }
 46 
 47     void reserve(int newCapacity)
 48     {
 49         if (newCapacity < theSize)        //至少和（样本大小）一样大
 50             return;
 51 
 52         Object *oldArray = objects;       //oldArray--用于复制旧数组内容
 53         objects = new Object[newCapacity];
 54         for (int k = 0; k < theSize; k++)
 55             objects[k] = oldArray[k];
 56 
 57         theCapacity = newCapacity;
 58         delete []oldArray;
 59     }
 60 
 61     Object& operator[] (int index)
 62     {
 63         return objects[index];
 64     }
 65     const Object& operator[] (int index) const
 66     {
 67         return objects[index];
 68     }
 69 
 70     bool empty() const {
 71         return size() == 0;
 72     }
 73     
 74     int size() const {
 75         return theSize;
 76     }
 77     int capacity() const {
 78         return theCapacity;
 79     }
 80     void push_back(const Object& x) {
 81         if (theSize == theCapacity)
 82             reserve(2 * theCapacity + 1);
 83         objects[theSize++] = x;
 84     }
 85     
 86     void pop_back() {
 87         theSize--;
 88     }
 89     const Object& back() const {
 90         return objects[theSize - 1];
 91     }
 92     
 93     typedef Object *iterator;
 94     typedef const Object *const_iterator;
 95 
 96     iterator begin() {
 97         return &objects[0];
 98     }
 99     const_iterator begin() const {
100         return &objects[0];
101     }
102     iterator end() {               //尾后的不存在的指针
103         return &objects[size()];     
104     }
105     const_iterator end() const {
106         return &objects[size()];
107     }
108 };
109 
110 int main()
111 {
112     Vector<int> test;
113     int data;
114     while (cin >> data)
115     {
116         test.push_back(data);
117     }
118     Vector<int>::iterator it;
119     for (it = test.begin(); it != test.end(); ++it)
120         cout << *it << " ";
121     cout << endl;
122     cout << "pop_one.....\n";
123     test.pop_back();
124     cout << test.back() << endl;
125     return 0;
126 }