#include <utility>
template <typename T1,typename T2>
class pair
{
??? 1.空構造
??? 2.雙參數構造
???? 3.拷貝構造
????? 4.swap交換
5.內含2個T1,T2型 變量（first ,second）;
}
pair 是struct ,所有成員公有
template <typename T1,typename T2>

??? pair<T1,T2> make_pair(const T1&,const T2&)

?? 操作符重載模版
make_pair(a,b);//按值返回個pair< >對象;
make_pair<int,float >(a,b);

auto_ptr<T> ptr(new int);//智能指針類???

輔助函數模板
max ,min, swap

template<class Type>   void swap(      Type& _Left,       Type& _Right   );   #include <algorithm>


4個比較算子
 #include <utility>
 using namespace rel_ops; 
 就重載了這幾個算子

template<Class Type>   bool operator!=(      const Type& _Left,      const Type& _Right);template<class Type1, class Type2>   bool operator!=(      const pair<Type1, Type2>& _Left,      const pair<Type1, Type2>& _Right   );
   非pair<> 的在 std::rel_ops中



?1以下是迭代器基類
?2template<class?_Category,
?3????class?_Ty,
?4????class?_Diff?=?ptrdiff_t,
?5????class?_Pointer?=?_Ty?*,
?6????class?_Reference?=?_Ty&>
?7????????struct?iterator
?8????{????//?base?type?for?all?iterator?classes
?9????typedef?_Category?iterator_category;
10????typedef?_Ty?value_type;
11????typedef?_Diff?difference_type;
12????typedef?_Diff?distance_type;????//?retained
13????typedef?_Pointer?pointer;
14????typedef?_Reference?reference;
15????};
16

?1template<class?_Ty>
?2????class?allocator
?3//基類，是個空結構
?4????????:?public?_Allocator_base<_Ty>
?5????{????//?generic?allocator?for?objects?of?class?_Ty
?6public:
?7????typedef?_Allocator_base<_Ty>?_Mybase;
?8????typedef?typename?_Mybase::value_type?value_type;
?9
10
11????typedef?value_type?_FARQ?*pointer;
12????typedef?value_type?_FARQ&?reference;
13????typedef?const?value_type?_FARQ?*const_pointer;
14????typedef?const?value_type?_FARQ&?const_reference;
15
16????typedef?_SIZT?size_type;
17????typedef?_PDFT?difference_type;
18
19????template<class?_Other>
20????????struct?rebind
21????????{????//?convert?an?allocator<_Ty>?to?an?allocator?<_Other>
22????????typedef?allocator<_Other>?other;
23????????};
24
25????pointer?address(reference?_Val)?const
26????????{????//?return?address?of?mutable?_Val
27????????return?(&_Val);
28????????}
29
30????const_pointer?address(const_reference?_Val)?const
31????????{????//?return?address?of?nonmutable?_Val
32????????return?(&_Val);
33????????}
34
35????allocator()
36????????{????//?construct?default?allocator?(do?nothing)
37????????}
38
39????allocator(const?allocator<_Ty>&)
40????????{????//?construct?by?copying?(do?nothing)
41????????}
42
43????template<class?_Other>
44????????allocator(const?allocator<_Other>&)
45????????{????//?construct?from?a?related?allocator?(do?nothing)
46????????}
47
48????template<class?_Other>
49????????allocator<_Ty>&?operator=(const?allocator<_Other>&)
50????????{????//?assign?from?a?related?allocator?(do?nothing)
51????????return?(*this);
52????????}
53
54????void?deallocate(pointer?_Ptr,?size_type)
55????????{????//?deallocate?object?at?_Ptr,?ignore?size
56????????operator?delete(_Ptr);
57????????}
58
59????pointer?allocate(size_type?_Count)
60????????{????//?allocate?array?of?_Count?elements
61????????return?(_Allocate(_Count,?(pointer)0));
62????????}
63
64????pointer?allocate(size_type?_Count,?const?void?_FARQ?*)
65????????{????//?allocate?array?of?_Count?elements,?ignore?hint
66????????return?(allocate(_Count));
67????????}
68
69????void?construct(pointer?_Ptr,?const?_Ty&?_Val)
70????????{????//?construct?object?at?_Ptr?with?value?_Val
71????????_Construct(_Ptr,?_Val);
72????????}
73
74????void?destroy(pointer?_Ptr)
75????????{????//?destroy?object?at?_Ptr
76????????_Destroy(_Ptr);
77????????}
78
79????_SIZT?max_size()?const
80????????{????//?estimate?maximum?array?size
81????????_SIZT?_Count?=?(_SIZT)(-1)?/?sizeof?(_Ty);
82????????return?(0?<?_Count???_Count?:?1);
83????????}
84????};

以上是.net 2003 中 iterator 和 allocator 的代碼
可以看出 stl是借助allocate 模板來分配元素 空間的?


一個自定義迭代器，和自定義容器

類型萃取技術（迭代器中廣泛使用的技術）

? template <typename T>
?? struct iterator
{
??? typedef T? value_type;
};
template <typename T>
?struct iterator_trait
{
?????typedef? T ?typename? T::iterator::value_type?? value_type;
};

template <typename T>
typename iterator_trait<T>::value_type
?f(T)
{};

???萃取機 iterator_trait<迭代器〉??快速的從迭代器中 取出 迭代器實際類型
（very important)
???????