1
template
<
typename T1,typename T2
>
2
class
mypair :
public
pair
<
T1,T2
>
3
{
4
public
:
5
inline mypair ():pair()
{}
;
6
inline mypair(
const
T1
&
a,
const
T2
&
b):pair
<
T1,T2
>
(a,b)
{}
;
7
inline mypair(
const
mypair
<
T1,T2
>
&
a):pair
<
T1,T2
>
(a)
{}
;
8
friend ostream
&
operator
<<
<
T1,T2
>
(ostream
&
os,mypair
<
T1,T2
>
&
p);
9
protected
:
10
private
:
11
}
;
12
template
<
typename T1,typename T2
>
13
ostream
&
operator
<<
(ostream
&
os,mypair
<
T1,T2
>&
p)
14
{
15
os
<<
"
\n cout pair
"
;
16
os
<<
endl
<<
"
"
<<
p.first;
17
os
<<
endl
<<
"
"
<<
p.second;
18
return
os;
19
}
20
21
22
int
_tmain(
int
argc, _TCHAR
*
argv[])
23
{
24
f();
25
mypair
<
int
,
float
>
a(
1
,
2.0333
);
26
mypair
<
int
,
float
>
b(
2
,
6.04343
);
27
mypair
<
int
,
float
>
c(b);
28
cout
<<
a;
29
cout
<<
b;
30
cout
<<
c;
31
a.swap(b);
32
cout
<<
a;
33
cout
<<
b;
34
35
cout
<<
(a
==
b);
36
37
return
0
;
38
}
39
#include <utility>
template <typename T1,typename T2>
class pair
{
1.空构造
2.双参数构造
3.拷贝构造
4.swap交换
5.内含2个T1,T2型 变量（first ,second）;
}
pair 是struct ,所有成员公有
template <typename T1,typename T2>
pair<T1,T2> make_pair(const T1&,const T2&)
操作符重载模版
make_pair(a,b);//按值返回个pair< >对象;
make_pair<int,float >(a,b);
auto_ptr<T> ptr(new int);//智能指针类
辅助函数模板
max ,min, swap
template<class Type> void swap( Type& _Left, Type& _Right ); #include <algorithm>
4个比较算子
#include <utility>
using namespace rel_ops;
就重载了这几个算子
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以下是迭代器基类
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//基类，是个空结构
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 的代码
可以看出 stl是借助allocate 模板来分配元素 空间的
一个自定义迭代器，和自定义容器
1template<typename item>
2class maniter;
3
4template <typename T>
5class man
6{
7public:
8 typedef maniter<T> iterator ;
9 man()
10 {
11 array=NULL;
12 size=0;
13 }
14 iterator begin()
15 {
16 iterator *pt =new iterator;
17 pt->p=array;
18 return *pt;
19 }
20 iterator end()
21 {
22 iterator *pt=new iterator;
23 pt->p=array+sizeof(T)*size;
24 return *pt;
25 }
26 man(int count)
27 {
28
29 array=new T [count];
30
31 size=count;
32 for (int i=0;i<size;i++)
33 {
34
35 *(array+i)=i;
36 }
37
38 }
39 man(const man& a)
40 {
41
42
43 if(this!=&a)
44 {
45 size=a.size;
46
47 try{
48 array=new T[a.size];
49 }
50 catch (bad_alloc e) {
51
52 }
53 }
54 for (int i=0;i<a.size;i++)
55 {
56
57 *(array+i)=a.array[i];
58 }
59
60
61 }
62 void operator =(const man& a)
63 {
64
65
66 delete [] array;
67 array=new T [a.size];
68 size=a.size;
69 for (int i=0;i<a.size;i++)
70 {
71 *(array+i)=a.array[i];
72 }
73
74 //return *this;
75 }
76 ~man()
77 {
78 delete [] array;
79 size=0;
80 }
81 man<T>& operator++()
82 {
83 this->array++;
84 return *this;
85 }
86 const man<T> operator++(int )
87 {
88 man<T> temp=*this;
89 (this->array)++;
90 return temp;
91 }
92
93protected:
94 friend ostream& operator<< <T>(ostream& os,const man<T> & a);
95private:
96 T * array;
97 int size;
98};
99template <typename T>
100ostream& operator<<(ostream& os, const man<T>& a)
101{
102 cout<<"\n in printing man"<<endl;
103 if (!a.size)
104 {
105 cout<<"\n"<<" array is null";
106 }
107 for (int i=0;i<a.size;i++)
108 {
109
110 os<<" "<<a.array[i];
111 }
112 cout<<endl;
113 return os;
114 }
115
116template <typename it,typename T>
117it myfind(it begin, it end , const T& a)
118{
119 for (;begin!=end&&*begin!=a;++begin)
120 {}
121 return begin;
122}
123
124template<typename item>
125class maniter
126{
127public:
128 item* p;
129 maniter():p(0)
130 {
131
132 }
133 item& operator*(){return *p;};
134 item* operator->(){return p;};
135 item& operator++(){p++;return *p;};
136 item operator++(int){item temp=*this;this++;return temp;}
137 bool operator==(const maniter & ele)
138 {
139 return *p==*(ele.p);
140 }
141 bool operator!=(const maniter & ele)
142 {
143 return *p!=*(ele.p);
144 }
145
146protected:
147private:
148
149};
150int _tmain(int argc, _TCHAR* argv[])
151{
152/**//*
153 vector<man<int> > a;
154for (int i=1;i<10;++i)
155 {
156 cout<<"\n "<<i;
157 man<int>* manb=new man<int> (i);
158 a.push_back(*manb);
159 delete manb;
160
161 }
162 */
163 man<int > b(5);
164 cout<<(*myfind(b.begin(),b.end(),3));//very perfect,自定义迭代器成功实现
165 //迭代器就是包含容器节点指针的类模板对象，提供 *，->,++,--,==,!= （essential）操作的，这些操作需要迭代器
166 //对容器结构了解，如本列中maniter 就清楚知道man 类中的节点结构是个1维数组
167return 0;
168}
169
170 类型萃取技术（迭代器中广泛使用的技术）
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)
{};
萃取机 iterator_trait<迭代器〉 快速的从迭代器中 取出 迭代器实际类型
（very important)
posted on 2006-05-31 16:53
黄大仙 阅读(1203)
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