reverse_iterator 類別
類別範本是反覆運算器配接器,描述反向反覆運算器物件,其行為就像隨機存取或雙向反覆運算器一樣,只會反向運作。 它啟用範圍的向後周遊。
語法
template <class RandomIterator>
class reverse_iterator
參數
RandomIterator 代表要調整為反向運作的反覆運算器類型。
備註
現有的 C++ 標準程式庫容器也會定義 reverse_iterator
和 const_reverse_iterator
類型,並且具有可傳回反向迭代器的成員函式 rbegin
和 rend
。 這些迭代器有覆寫語意。 配 reverse_iterator
接器會補充這項功能,因為它提供插入語意,也可以與數據流搭配使用。
reverse_iterator
需要雙向反覆運算器的 ,不得呼叫任何只能搭配隨機存取反覆運算器使用的成員函operator+=
式 、operator+
、、 operator-=
operator-
或 operator[]
。
反覆運算器的範圍是 [first, last),其中左邊的方括弧表示包含第一個,右邊的括號表示包含最多但排除最後一個專案。 相同的元素會包含在反向序列 [rev - first, rev - last) 中,因此,如果 last 是序列中的一個過去結束元素,則反轉序列中的第一個元素 rev - 會指向 *(last - 1)。 將所有反向迭代器關聯至其基礎迭代器的識別為:
&*(reverse_iterator (i)) == &*(i - 1)。
實際上,這表示在反向序列中 reverse_iterator 會參考迭代器在原始序列中所參考項目之外 (右側) 一個位置的項目。 因此,如果迭代器定址序列 (2, 4, 6, 8) 中的項目 6,則 reverse_iterator
會定址反向序列 (8, 6, 4, 2) 中的項目 4。
建構函式
建構函式 | 描述 |
---|---|
reverse_iterator | 從基底迭代器建構預設的 reverse_iterator 或 reverse_iterator 。 |
Typedefs
類型名稱 | 描述 |
---|---|
difference_type | 類型,提供兩個參考同一容器內項目的 reverse_iterator 之間的差異。 |
iterator_type | 類型,提供 reverse_iterator 的基礎迭代器。 |
pointer | 類型,提供指向 reverse_iterator 定址的項目之指標。 |
reference | 類型,提供指向 reverse_iterator 定址的項目之參考。 |
成員函式
成員函數 | 描述 |
---|---|
base | 從其 reverse_iterator 復原基礎迭代器。 |
操作員
運算子 | 描述 |
---|---|
operator_star | 傳回 reverse_iterator 定址的項目。 |
operator+ | 將位移新增至迭代器,並傳回新的 reverse_iterator ,定址在新的位移位置中插入的項目。 |
operator++ | 遞增 reverse_iterator 至下一個項目。 |
operator+= | 加入 reverse_iterator 的指定位移。 |
operator- | 從 reverse_iterator 減去位移並傳回 reverse_iterator ,定址在位移位置上的項目。 |
算子-- | 遞減 reverse_iterator 至上一個項目。 |
operator-= | 從 reverse_iterator 減去指定位移。 |
operator-> | 傳回由 reverse_iterator 定址的項目之指標。 |
operator[] |
以指定的位置數目,從 reverse_iterator 定址的項目傳回項目位移的參考。 |
需求
Header:<iterator>
命名空間:std
reverse_iterator::base
從其 reverse_iterator
復原基礎迭代器。
RandomIterator base() const;
傳回值
構成 reverse_iterator
基礎的迭代器。
備註
將所有反向迭代器關聯至其基礎迭代器的識別為:
&*(reverse_iterator
i)) == &*(i - 1)。
實際上,這表示在反向序列中,reverse_iterator
將參考迭代器在原始序列中所參考項目之外 (右側) 某個位置的項目。 因此,如果迭代器定址序列 (2, 4, 6, 8) 中的項目 6,則 reverse_iterator
會定址反向序列 (8, 6, 4, 2) 中的項目 4。
範例
// reverse_iterator_base.cpp
// compile with: /EHsc
#include <iterator>
#include <algorithm>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for ( i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin ( ) ; vIter != vec.end ( ); vIter++ )
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
vector <int>::iterator pos, bpos;
pos = find ( vec.begin ( ), vec.end ( ), 6 );
cout << "The iterator pos points to: " << *pos << "." << endl;
typedef reverse_iterator<vector<int>::iterator>::iterator_type it_vec_int_type;
reverse_iterator<it_vec_int_type> rpos ( pos );
cout << "The reverse_iterator rpos points to: " << *rpos
<< "." << endl;
bpos = rpos.base ( );
cout << "The iterator underlying rpos is bpos & it points to: "
<< *bpos << "." << endl;
}
reverse_iterator::d ifference_type
類型,提供兩個參考同一容器內項目的 reverse_iterator
之間的差異。
typedef typename iterator_traits<RandomIterator>::difference_type difference_type;
備註
reverse_iterator
差異類型與迭代器差異類型相同。
類型是迭代器特性 typename iterator_traits
<RandomIterator>::pointer 的同義字。
範例
如需如何宣告和使用 difference_type
的範例,請參閱 reverse_iterator::operator[]
。
reverse_iterator::iterator_type
類型,提供 reverse_iterator
的基礎迭代器。
typedef RandomIterator iterator_type;
備註
此類型是範本參數 Iterator
的同義字。
範例
如需如何宣告及使用 iterator_type
的範例,請參閱 reverse_iterator::base。
reverse_iterator::operator*
傳回 reverse_iterator 定址的項目。
reference operator*() const;
傳回值
reverse_iterator 所定址的項目值。
備註
運算符會傳回 *( 目前 - 1)。
範例
// reverse_iterator_op_ref.cpp
// compile with: /EHsc
#include <iterator>
#include <algorithm>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for (i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin ( ) ; vIter != vec.end ( ); vIter++ )
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
vector <int>::iterator pos, bpos;
pos = find ( vec.begin ( ), vec.end ( ), 6 );
// Declare a difference type for a parameter
// declare a reference return type
reverse_iterator<vector<int>::iterator>::reference refpos = *pos;
cout << "The iterator pos points to: " << refpos << "." << endl;
}
reverse_iterator::operator+
將位移新增至迭代器,並傳回新的 reverse_iterator
,定址在新的位移位置中插入的項目。
reverse_iterator<RandomIterator> operator+(difference_type Off) const;
參數
關閉
要加入至反向迭代器的位移。
傳回值
為位移項目定址的 reverse_iterator
。
備註
唯有在 reverse_iterator
滿足隨機存取迭代器的需求時,才能使用此成員函式。
範例
// reverse_iterator_op_add.cpp
// compile with: /EHsc
#include <iterator>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for (i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin( ) ; vIter != vec.end( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
// Initializing reverse_iterators to the first element
vector <int>::reverse_iterator rVPOS1 = vec.rbegin ( );
cout << "The iterator rVPOS1 initially points to the first "
<< "element\n in the reversed sequence: "
<< *rVPOS1 << "." << endl;
vector <int>::reverse_iterator rVPOS2 =rVPOS1 + 2; // offset added
cout << "After the +2 offset, the iterator rVPOS2 points\n"
<< " to the 3rd element in the reversed sequence: "
<< *rVPOS2 << "." << endl;
}
The vector vec is: ( 2 4 6 8 10 ).
The vector vec reversed is: ( 10 8 6 4 2 ).
The iterator rVPOS1 initially points to the first element
in the reversed sequence: 10.
After the +2 offset, the iterator rVPOS2 points
to the 3rd element in the reversed sequence: 6.
reverse_iterator::operator++
將 reverse_iterator 遞增至上一個項目。
reverse_iterator<RandomIterator>& operator++();
reverse_iterator<RandomIterator> operator++(int);
傳回值
第一個運算子會傳回前置遞增的 reverse_iterator
,而第二個後置遞增運算子會傳回遞增的 reverse_iterator
複本。
備註
唯有在 reverse_iterator
滿足雙向迭代器的需求時,才能使用此成員函式。
範例
// reverse_iterator_op_incr.cpp
// compile with: /EHsc
#include <iterator>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for ( i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i - 1 );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin( ) ; vIter != vec.end( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
// Initializing reverse_iterators to the last element
vector <int>::reverse_iterator rVPOS1 = vec.rbegin( );
cout << "The iterator rVPOS1 initially points to the first "
<< "element\n in the reversed sequence: "
<< *rVPOS1 << "." << endl;
rVPOS1++; // postincrement, preincrement: ++rVPSO1
cout << "After incrementing, the iterator rVPOS1 points\n"
<< " to the second element in the reversed sequence: "
<< *rVPOS1 << "." << endl;
}
The vector vec is: ( 1 3 5 7 9 ).
The vector vec reversed is: ( 9 7 5 3 1 ).
The iterator rVPOS1 initially points to the first element
in the reversed sequence: 9.
After incrementing, the iterator rVPOS1 points
to the second element in the reversed sequence: 7.
reverse_iterator::operator+=
加入 reverse_iterator 的指定位移。
reverse_iterator<RandomIterator>& operator+=(difference_type Off);
參數
關閉
要遞增迭代器的位移。
傳回值
由 reverse_iterator
定址之項目的參考。
範例
// reverse_iterator_op_addoff.cpp
// compile with: /EHsc
#include <iterator>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for (i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin( ) ; vIter != vec.end( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
// Initializing reverse_iterators to the last element
vector <int>::reverse_iterator rVPOS1 = vec.rbegin ( );
cout << "The iterator rVPOS1 initially points to the first "
<< "element\n in the reversed sequence: "
<< *rVPOS1 << "." << endl;
rVPOS1+=2; // addition of an offset
cout << "After the +2 offset, the iterator rVPOS1 now points\n"
<< " to the third element in the reversed sequence: "
<< *rVPOS1 << "." << endl;
}
The vector vec is: ( 2 4 6 8 10 ).
The vector vec reversed is: ( 10 8 6 4 2 ).
The iterator rVPOS1 initially points to the first element
in the reversed sequence: 10.
After the +2 offset, the iterator rVPOS1 now points
to the third element in the reversed sequence: 6.
reverse_iterator::operator-
從 reverse_iterator
減去位移並傳回 reverse_iterator
,定址在位移位置上的項目。
reverse_iterator<RandomIterator> operator-(difference_type Off) const;
參數
關閉
要從 reverse_iterator 中減去的位移。
傳回值
為位移項目定址的 reverse_iterator
。
備註
唯有在 reverse_iterator
滿足隨機存取迭代器的需求時,才能使用此成員函式。
範例
// reverse_iterator_op_sub.cpp
// compile with: /EHsc
#include <iterator>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for ( i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 3 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin( ) ; vIter != vec.end( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
// Initializing reverse_iterators to the first element
vector <int>::reverse_iterator rVPOS1 = vec.rend ( ) - 1;
cout << "The iterator rVPOS1 initially points to the last "
<< "element\n in the reversed sequence: "
<< *rVPOS1 << "." << endl;
vector <int>::reverse_iterator rVPOS2 =rVPOS1 - 2; // offset subtracted
cout << "After the -2 offset, the iterator rVPOS2 points\n"
<< " to the 2nd element from the last in the reversed sequence: "
<< *rVPOS2 << "." << endl;
}
The vector vec is: ( 3 6 9 12 15 ).
The vector vec reversed is: ( 15 12 9 6 3 ).
The iterator rVPOS1 initially points to the last element
in the reversed sequence: 3.
After the -2 offset, the iterator rVPOS2 points
to the 2nd element from the last in the reversed sequence: 9.
reverse_iterator::operator--
將 reverse_iterator 遞減至上一個項目。
reverse_iterator<RandomIterator>& operator--();
reverse_iterator<RandomIterator> operator--(int);
傳回值
第一個運算子會傳回前置遞減的 reverse_iterator
,而第二個後置遞減運算子會傳回遞減的 reverse_iterator
複本。
備註
唯有在 reverse_iterator
滿足雙向迭代器的需求時,才能使用此成員函式。
範例
// reverse_iterator_op_decr.cpp
// compile with: /EHsc
#include <iterator>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for (i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i - 1 );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin( ) ; vIter != vec.end( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
// Initializing reverse_iterators to the first element
vector <int>::reverse_iterator rVPOS1 = vec.rend ( ) - 1;
cout << "The iterator rVPOS1 initially points to the last "
<< "element\n in the reversed sequence: "
<< *rVPOS1 << "." << endl;
rVPOS1--; // postdecrement, predecrement: --rVPSO1
cout << "After the decrement, the iterator rVPOS1 points\n"
<< " to the next-to-last element in the reversed sequence: "
<< *rVPOS1 << "." << endl;
}
The vector vec is: ( 1 3 5 7 9 ).
The vector vec reversed is: ( 9 7 5 3 1 ).
The iterator rVPOS1 initially points to the last element
in the reversed sequence: 1.
After the decrement, the iterator rVPOS1 points
to the next-to-last element in the reversed sequence: 3.
reverse_iterator::operator-=
從 reverse_iterator
減去指定位移。
reverse_iterator<RandomIterator>& operator-=(difference_type Off);
參數
關閉
要從 reverse_iterator
中減去的位移。
備註
唯有在 reverse_iterator
滿足隨機存取迭代器的需求時,才能使用此成員函式。
運算子會 評估目前的 + Off ,然後傳 *this
回 。
範例
// reverse_iterator_op_suboff.cpp
// compile with: /EHsc
#include <iterator>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for (i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 3 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin( ) ; vIter != vec.end( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
// Initializing reverse_iterators to the first element
vector <int>::reverse_iterator rVPOS1 = vec.rend ( ) - 1;
cout << "The iterator rVPOS1 initially points to the last "
<< "element\n in the reversed sequence: "
<< *rVPOS1 << "." << endl;
rVPOS1-=2; // Subtraction of an offset
cout << "After the -2 offset, the iterator rVPOS1 now points\n"
<< " to the 2nd element from the last in the reversed sequence: "
<< *rVPOS1 << "." << endl;
}
The vector vec is: ( 3 6 9 12 15 ).
The vector vec reversed is: ( 15 12 9 6 3 ).
The iterator rVPOS1 initially points to the last element
in the reversed sequence: 3.
After the -2 offset, the iterator rVPOS1 now points
to the 2nd element from the last in the reversed sequence: 9.
reverse_iterator::operator->
傳回由 reverse_iterator
定址的項目之指標。
pointer operator->() const;
傳回值
由 reverse_iterator
定址之項目的指標。
備註
第一個運算子會傳回 &**this
。
範例
// reverse_iterator_ptrto.cpp
// compile with: /EHsc
#include <iterator>
#include <algorithm>
#include <vector>
#include <utility>
#include <iostream>
int main( )
{
using namespace std;
typedef vector<pair<int,int> > pVector;
pVector vec;
vec.push_back(pVector::value_type(1,2));
vec.push_back(pVector::value_type(3,4));
vec.push_back(pVector::value_type(5,6));
pVector::iterator pvIter;
cout << "The vector vec of integer pairs is:\n( ";
for ( pvIter = vec.begin ( ) ; pvIter != vec.end ( ); pvIter++)
cout << "( " << pvIter -> first << ", " << pvIter -> second << ") ";
cout << ")" << endl << endl;
pVector::reverse_iterator rpvIter;
cout << "The vector vec reversed is:\n( ";
for ( rpvIter = vec.rbegin( ) ; rpvIter != vec.rend( ); rpvIter++ )
cout << "( " << rpvIter -> first << ", " << rpvIter -> second << ") ";
cout << ")" << endl << endl;
pVector::iterator pos = vec.begin ( );
pos++;
cout << "The iterator pos points to:\n( " << pos -> first << ", "
<< pos -> second << " )" << endl << endl;
pVector::reverse_iterator rpos (pos);
// Use operator -> with return type: why type int and not int*
int fint = rpos -> first;
int sint = rpos -> second;
cout << "The reverse_iterator rpos points to:\n( " << fint << ", "
<< sint << " )" << endl;
}
The vector vec of integer pairs is:
( ( 1, 2) ( 3, 4) ( 5, 6) )
The vector vec reversed is:
( ( 5, 6) ( 3, 4) ( 1, 2) )
The iterator pos points to:
( 3, 4 )
The reverse_iterator rpos points to:
( 1, 2 )
reverse_iterator::operator[]
以指定的位置數目,從 reverse_iterator
定址的項目傳回項目位移的參考。
reference operator[](difference_type Off) const;
參數
關閉
reverse_iterator
位址的位移。
傳回值
項目位移的參考。
備註
運算子會傳*回 ( + *this
Off
。
範例
// reverse_iterator_ret_ref.cpp
// compile with: /EHsc
#include <iterator>
#include <algorithm>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for (i = 1 ; i < 6 ; ++i )
{
vec.push_back ( 2 * i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin ( ) ; vIter != vec.end ( ); vIter++ )
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
vector <int>::iterator pos;
pos = find ( vec.begin ( ), vec.end ( ), 8 );
reverse_iterator<vector<int>::iterator> rpos ( pos );
// Declare a difference type for a parameter
reverse_iterator<vector<int>::iterator>::difference_type diff = 2;
cout << "The iterator pos points to: " << *pos << "." << endl;
cout << "The iterator rpos points to: " << *rpos << "." << endl;
// Declare a reference return type & use operator[]
reverse_iterator<vector<int>::iterator>::reference refrpos = rpos [diff];
cout << "The iterator rpos now points to: " << refrpos << "." << endl;
}
The vector vec is: ( 2 4 6 8 10 ).
The vector vec reversed is: ( 10 8 6 4 2 ).
The iterator pos points to: 8.
The iterator rpos points to: 6.
The iterator rpos now points to: 2.
reverse_iterator::p ointer
類型,提供指向 reverse_iterator
定址的項目之指標。
typedef typename iterator_traits<RandomIterator>::pointer pointer;
備註
類型是迭代器特性 typename iterator_traits
<RandomIterator>::pointer 的同義字。
範例
// reverse_iterator_pointer.cpp
// compile with: /EHsc
#include <iterator>
#include <algorithm>
#include <vector>
#include <utility>
#include <iostream>
int main( )
{
using namespace std;
typedef vector<pair<int,int> > pVector;
pVector vec;
vec.push_back( pVector::value_type( 1,2 ) );
vec.push_back( pVector::value_type( 3,4 ) );
vec.push_back( pVector::value_type( 5,6 ) );
pVector::iterator pvIter;
cout << "The vector vec of integer pairs is:\n" << "( ";
for ( pvIter = vec.begin ( ) ; pvIter != vec.end ( ); pvIter++)
cout << "( " << pvIter -> first << ", " << pvIter -> second << ") ";
cout << ")" << endl;
pVector::reverse_iterator rpvIter;
cout << "\nThe vector vec reversed is:\n" << "( ";
for ( rpvIter = vec.rbegin( ) ; rpvIter != vec.rend( ); rpvIter++)
cout << "( " << rpvIter -> first << ", " << rpvIter -> second << ") ";
cout << ")" << endl;
pVector::iterator pos = vec.begin ( );
pos++;
cout << "\nThe iterator pos points to:\n"
<< "( " << pos -> first << ", "
<< pos -> second << " )" << endl;
pVector::reverse_iterator rpos (pos);
cout << "\nThe iterator rpos points to:\n"
<< "( " << rpos -> first << ", "
<< rpos -> second << " )" << endl;
}
The vector vec of integer pairs is:
( ( 1, 2) ( 3, 4) ( 5, 6) )
The vector vec reversed is:
( ( 5, 6) ( 3, 4) ( 1, 2) )
The iterator pos points to:
( 3, 4 )
The iterator rpos points to:
( 1, 2 )
reverse_iterator::reference
類型,提供指向 reverse_iterator 定址之項目的參考。
typedef typename iterator_traits<RandomIterator>::reference reference;
備註
此類型與反覆運算器特性類型名稱 iterator_traits<RandomIterator>::reference
同義。
範例
如需如何宣告和使用 reference
的範例,請參閱reverse_iterator::operator[]
或reverse_iterator::operator* 。
reverse_iterator::reverse_iterator
從基底迭代器建構預設的 reverse_iterator
或 reverse_iterator
。
reverse_iterator();
explicit reverse_iterator(RandomIterator right);
template <class Type>
reverse_iterator(const reverse_iterator<Type>& right);
參數
right
要調整為 reverse_iterator
的迭代器。
傳回值
調整基礎迭代器的預設 reverse_iterator
或 reverse_iterator
。
備註
將所有反向迭代器關聯至其基礎迭代器的識別為:
&*(reverse_iterator (i)) == &*(i-1)
.
實際上,這表示在反向序列中 reverse_iterator 會參考迭代器在原始序列中所參考項目之外 (右側) 一個位置的項目。 因此,如果迭代器定址序列 (2, 4, 6, 8) 中的項目 6,則 reverse_iterator
會定址反向序列 (8, 6, 4, 2) 中的項目 4。
範例
// reverse_iterator_reverse_iterator.cpp
// compile with: /EHsc
#include <iterator>
#include <algorithm>
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
int i;
vector<int> vec;
for ( i = 1 ; i < 6 ; ++i )
{
vec.push_back ( i );
}
vector <int>::iterator vIter;
cout << "The vector vec is: ( ";
for ( vIter = vec.begin ( ) ; vIter != vec.end ( ); vIter++)
cout << *vIter << " ";
cout << ")." << endl;
vector <int>::reverse_iterator rvIter;
cout << "The vector vec reversed is: ( ";
for ( rvIter = vec.rbegin( ) ; rvIter != vec.rend( ); rvIter++)
cout << *rvIter << " ";
cout << ")." << endl;
vector <int>::iterator pos;
pos = find ( vec.begin ( ), vec.end ( ), 4 );
cout << "The iterator pos = " << *pos << "." << endl;
vector <int>::reverse_iterator rpos ( pos );
cout << "The reverse_iterator rpos = " << *rpos
<< "." << endl;
}