STL学习--stack

简介

stack是一中后入先出（LIFO）的数据结构，它只有一个出口，只可以对顶端元素进行操作。STL底层默认基于deque容器实现。

在创建适配器时，通过将一个顺序容器指定为适配器的第二个类型实参，可覆盖默认的容器类型。

stack< string, vector<string> > str_stk; // 由vector实现的stack

stack< string, list<string> > str_stk; // 由list实现的stack

stack是由底部容器完成的所有操作，因此是容器适配器。

特性

后入先出（LIFO）

只可对顶端元素进行操作，没有迭代器。

常用操作

s.empty()如果栈为空，则返回 true，否则返回 stacks.size()返回栈中元素的个数s.pop()删除栈顶元素的值，但不返回其值s.top()返回栈顶元素的值，但不删除该元素s.push(item)在栈顶压入新元素

源码（STL3.3）

/* * * 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#include <sequence_concepts.h>__STL_BEGIN_NAMESPACE// Forward declarations of operators == and <, needed for friend declaration.template <class _Tp,           class _Sequence __STL_DEPENDENT_DEFAULT_TMPL(deque<_Tp>) >class stack;template <class _Tp, class _Seq>bool operator==(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);template <class _Tp, class _Seq>bool operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y);template <class _Tp, class _Sequence>class stack {  // requirements:  __STL_CLASS_REQUIRES(_Tp, _Assignable);  __STL_CLASS_REQUIRES(_Sequence, _BackInsertionSequence);  typedef typename _Sequence::value_type _Sequence_value_type;  __STL_CLASS_REQUIRES_SAME_TYPE(_Tp, _Sequence_value_type);#ifdef __STL_MEMBER_TEMPLATES  template <class _Tp1, class _Seq1>  friend bool operator== (const stack<_Tp1, _Seq1>&,                          const stack<_Tp1, _Seq1>&);  template <class _Tp1, class _Seq1>  friend bool operator< (const stack<_Tp1, _Seq1>&,                         const stack<_Tp1, _Seq1>&);#else /* __STL_MEMBER_TEMPLATES */  friend bool __STD_QUALIFIER  operator== __STL_NULL_TMPL_ARGS (const stack&, const stack&);  friend bool __STD_QUALIFIER  operator< __STL_NULL_TMPL_ARGS (const stack&, const stack&);#endif /* __STL_MEMBER_TEMPLATES */public:  typedef typename _Sequence::value_type      value_type;  typedef typename _Sequence::size_type       size_type;  typedef          _Sequence                  container_type;  typedef typename _Sequence::reference       reference;  typedef typename _Sequence::const_reference const_reference;protected:  _Sequence c;public:  stack() : c() {}  explicit stack(const _Sequence& __s) : c(__s) {}  bool empty() const { return c.empty(); }  size_type size() const { return c.size(); }  reference top() { return c.back(); }  const_reference top() const { return c.back(); }  void push(const value_type& __x) { c.push_back(__x); }  void pop() { c.pop_back(); }};template <class _Tp, class _Seq>bool operator==(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y){  return __x.c == __y.c;}template <class _Tp, class _Seq>bool operator<(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y){  return __x.c < __y.c;}#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDERtemplate <class _Tp, class _Seq>bool operator!=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y){  return !(__x == __y);}template <class _Tp, class _Seq>bool operator>(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y){  return __y < __x;}template <class _Tp, class _Seq>bool operator<=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y){  return !(__y < __x);}template <class _Tp, class _Seq>bool operator>=(const stack<_Tp,_Seq>& __x, const stack<_Tp,_Seq>& __y){  return !(__x < __y);}#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */__STL_END_NAMESPACE#endif /* __SGI_STL_INTERNAL_STACK_H */// Local Variables:// mode:C++// End: