W3cubDocs

/C++

C++ named requirements: ReversibleContainer

A ReversibleContainer is a Container that has iterators that meet the requirements of either LegacyBidirectionalIterator or LegacyRandomAccessIterator. Such iterators allow a ReversibleContainer to be iterated over in reverse.

Requirements

`X`	Container type
`T`	Element type
`a`	Objects of type `X`

Types

Expression	Return type	Conditions
`X::reverse_iterator`	Iterator type whose value type is `T`	`reverse_iterator<iterator>`
`X::const_reverse_iterator`	Constant iterator type whose value type is `T`	`reverse_iterator<const_iterator>`

Member functions

Expression	Return type	Conditions	Complexity
`a.rbegin()`	`reverse_iterator`; `const_reverse_iterator` for constant `a`	`reverse_iterator(end())`	Constant
`a.rend()`	`reverse_iterator`; `const_reverse_iterator` for constant `a`	`reverse_iterator(begin())`	Constant
`a.crbegin()`	`const_reverse_iterator`	`const_cast<X const&>(a).rbegin()`	Constant
`a.crend()`	`const_reverse_iterator`	`const_cast<X const&>(a).rend()`	Constant

Standard library

Example

The following example iterates over a vector (which has random-access iterators) in reverse.

#include <iostream>
#include <vector>
 
int main()
{
    std::vector<int> v = {3, 1, 4, 1, 5, 9};
 
    for (std::vector<int>::const_reverse_iterator i{v.crbegin()}; i != v.crend(); ++i)
        std::cout << *i << ' ';
    std::cout << '\n';
}

Output:

9 5 1 4 1 3

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/named_req/ReversibleContainer