public member function
<iterator>
| default (1) | reverse_iterator(); |
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| initialization (2) | explicit reverse_iterator (iterator_type it); |
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| copy (3) | template <class Iter> reverse_iterator (const reverse_iterator<Iter>& rev_it); |
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Constructs reverse_iterator object
Constructs a reverse iterator object:
- (1) default constructor
- Constructs a reverse iterator that points to no object.
The internal base iterator is value-initialized.
- (2) initalization constructor
- Constructs a reverse iterator from some original iterator it. The behavior of the constructed object replicates the original, except that it iterates through its pointed elements in the reverse order.
- (3) copy / type-cast constructor
- Constructs a reverse iterator from some other reverse iterator. The constructed object keeps the same sense of iteration as rev_it.
Parameters
- it
- An iterator, whose sense of iteration is inverted in the constructed object.
Member type iterator_type is the underlying bidirectional iterator type (the class template parameter: Iterator).
- rev_it
- An iterator of a reverse_iterator type, whose sense of iteration is preserved.
Example
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// reverse_iterator example
#include <iostream> // std::cout
#include <iterator> // std::reverse_iterator
#include <vector> // std::vector
int main () {
std::vector<int> myvector;
for (int i=0; i<10; i++) myvector.push_back(i);
typedef std::vector<int>::iterator iter_type;
// ? 0 1 2 3 4 5 6 7 8 9 ?
iter_type from (myvector.begin()); // ^
// ------>
iter_type until (myvector.end()); // ^
//
std::reverse_iterator<iter_type> rev_until (from); // ^
// <------
std::reverse_iterator<iter_type> rev_from (until); // ^
std::cout << "myvector:";
while (rev_from != rev_until)
std::cout << ' ' << *rev_from++;
std::cout << '\n';
return 0;
}
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Output:
myvector: 9 8 7 6 5 4 3 2 1 0
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Exception safety
Provides the same level of guarantee as the proper constructor of the base iterator.