标签：扩容 arrays bool int array 原理 线性 temp while
1.栈的原理
后进先出（LIFO-last in first out）:最后插入的元素最先出来，是一种“操作受限”的线性表，只允许在端插入和删除数据
2.栈的实现
顺序栈：用数组实现，顺序栈需要动态扩容，在初始化时需要给定一个固定大小的数组，当栈大于固定大小时需要扩充数组的大小。
template<class T> class MyArrayStack { public: MyArrayStack(); ~MyArrayStack(); public: bool empty() const; void push(T const&); void pop(); T top() const; protected: T *m_pArrayData; int m_nSize; int m_nMaxSize; }; template<class T> MyArrayStack<T>::MyArrayStack(){ m_nSize = 0; m_nMaxSize = 2; m_pArrayData = new T[m_nMaxSize]; } template<class T> MyArrayStack<T>::~MyArrayStack(){ delete []m_pArrayData; m_pArrayData = NULL; } template<class T> bool MyArrayStack<T>::empty() const { if(m_nSize == 0) { return true; } return false; } template<class T> void MyArrayStack<T>::pop() { if(m_nSize <= 0) return ; if(m_nSize < m_nMaxSize/2) { m_nMaxSize /= 2; T *pTmp = new T[m_nMaxSize]; memcpy(pTmp, m_pArrayData, sizeof(T)*m_nSize); delete []m_pArrayData; m_pArrayData = NULL; m_pArrayData = pTmp; } if(m_nSize != 0) { m_nSize--; } } template<class T> void MyArrayStack<T>::push(T const& param) { if(m_nSize >= m_nMaxSize) { m_nMaxSize *= 2; T *pTmp = new T[m_nMaxSize]; memcpy(pTmp, m_pArrayData, sizeof(T)*m_nSize); delete []m_pArrayData; m_pArrayData = NULL; m_pArrayData = pTmp; } m_pArrayData[m_nSize++] = param; } template<class T> T MyArrayStack<T>::top() const { return m_pArrayData[m_nSize-1]; }
链式栈：用链表实现
template<class T> struct Node { T nNum; Node* pNext; Node() { pNext = NULL; } }; template<class T> class MyListStack { public: MyListStack(); ~MyListStack(); public: bool empty() const; void push(T const&); void pop(); T top() const; protected: Node<T>* pHead; }; template<class T> MyListStack<T>::MyListStack() { pHead = NULL; } template<class T> MyListStack<T>::~MyListStack(){ while(pHead != NULL) { Node<T> *pTmp = pHead->pNext; delete pHead; pHead = pTmp; } } template<class T> bool MyListStack<T>::empty() const { if(pHead == NULL) { return true; } return false; } template<class T> void MyListStack<T>::pop() { if(pHead != NULL) { Node<T> *pTmp = pHead->pNext; delete pHead; pHead = pTmp; } } template<class T> void MyListStack<T>::push(T const& param) { if(pHead == NULL) { pHead = new Node<T>; pHead->nNum = param; pHead->pNext = NULL; } else { Node<T> *pTmp = new Node<T>; pTmp->nNum = param; pTmp->pNext = pHead; pHead = pTmp; } } template<class T> T MyListStack<T>::top() const { return pHead->nNum; }
可关注公众号了解更多的面试技巧
标签：扩容 arrays bool int array 原理 线性 temp while
原文地址：https://www.cnblogs.com/yew0/p/11600687.html
