stl_stack.h

stl_stack.h// Filename:    stl_stack.h// Comment By:  凝霜// E-mail:      [e-mail]// Blog:        http://blog.csdn.net/mdl13412////////////////////////////////////////////////////////////////////////////////// stack是一种先进后出(First In Last Out, FILO)的数据结构, 其只有一个出口// 支持对栈顶元素的追加, 弹出, 获取, 但是不提供对其它位置元素的访问////////////////////////////////////////////////////////////////////////////////// 以下为使用deque时的布局//// 栈底                      当前栈顶                         预留的内存边界// ↓                            ↓                                 ↓// --------------------------------------------------------------------// |   |   | ...... |   |   |   |   |   |   |   | ......  |   |   | X |// --------------------------------------------------------------------//                              ↑   ↑                             ↑//                              |   |                             |//                              |   -------------------------------//                              |    这里是尚未使用的预留内存, 可能为0//                              |//                       仅支持在这里进行push(), pop(), top()操作/////////////////////////////////////////////////////////////////////////////////* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation.  Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose.  It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996,1997 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation.  Silicon Graphics makes no * representations about the suitability of this software for any * purpose.  It is provided "as is" without express or implied warranty. *//* NOTE: This is an internal header file, included by other STL headers. *   You should not attempt to use it directly. */#ifndef __SGI_STL_INTERNAL_STACK_H#define __SGI_STL_INTERNAL_STACK_H__STL_BEGIN_NAMESPACE// 如果编译器不能根据前面模板参数推导出后面使用的默认参数类型,// 那么就需要手工指定, 本实作stack内部容器默认使用deque// 选用deque可以在存储空间不足时可以动态增加, 而且代价很低#ifndef __STL_LIMITED_DEFAULT_TEMPLATEStemplate <class T, class Sequence = deque<T> >#elsetemplate <class T, class Sequence>#endifclass stack{  // 特化的全局运算符, 提供operator==和<重载则构建出所有运算符  // 其具体细节见<stl_pair.h>中的说明  friend bool operator== __STL_NULL_TMPL_ARGS (const stack&, const stack&);  friend bool operator< __STL_NULL_TMPL_ARGS (const stack&, const stack&);public:  // 由于stack仅支持对栈顶元素的操作, 所以不定义STL要求的  // pointer, iterator, difference_type  typedef typename Sequence::value_type value_type;  typedef typename Sequence::size_type size_type;  typedef typename Sequence::reference reference;  typedef typename Sequence::const_reference const_reference;protected:  Sequence c;   // 这个是我们实际维护的容器public:  // 下面的操作完全使用内部容器的成员函数实现  // 这再次体现了STL高度的可复用性:-)  // 判断stack是否为空  bool empty() const { return c.empty(); }  // stack中元素个数  size_type size() const { return c.size(); }  // 返回栈顶元素, 注意这里返回的是引用!!!  reference top() { return c.back(); }  const_reference top() const { return c.back(); }  // 在栈顶追加新元素  void push(const value_type& x) { c.push_back(x); }  // 移除栈顶元素, 注意不返回元素的引用,  // 很多初学者随机用此容器时经常误认为pop()操作同时会返回栈顶元素的引用  void pop() { c.pop_back(); }};// 判断两个stack是否相等, 就要测试其内部维护容器是否相等// x.c == y.c会调用容器重载的operator ==template <class T, class Sequence>bool operator==(const stack<T, Sequence>& x, const stack<T, Sequence>& y){  return x.c == y.c;}template <class T, class Sequence>bool operator<(const stack<T, Sequence>& x, const stack<T, Sequence>& y){  return x.c < y.c;}__STL_END_NAMESPACE#endif /* __SGI_STL_INTERNAL_STACK_H */// Local Variables:// mode:C++// End: