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std::ranges::subrange<I,S,K>::prev

From cppreference.com
< cpp‎ | ranges‎ | subrange
 
 
Ranges library
Range adaptors
 
 
constexpr subrange prev( std::iter_difference_t<I> n = 1 ) const
    requires std::bidirectional_iterator<I>;
(since C++20)

Returns a copy of *this whose begin_ is decremented (or incremented if n is negative). The actual decrement (or increment) operation is performed by advance(). Equivalent to:

auto tmp = *this;
tmp.advance(-n);
return tmp;
.

Contents

[edit] Parameters

n - number of decrements of the iterator

[edit] Return value

As described above.

[edit] Notes

The difference between this function and advance() is that the latter performs the decrement (or increment) in place.

[edit] Example

#include <iterator>
#include <list>
#include <print>
#include <ranges>
 
int main()
{
    std::list list{1, 2, 3, 4, 5};
    std::ranges::subrange sub{std::next(list.begin(), 2), std::prev(list.end(), 2)};
    std::println("{} {} {}", sub, sub.prev(), sub.prev(2));
}

Output:

[3] [2, 3] [1, 2, 3]

[edit] See also

obtains a copy of the subrange with its iterator advanced by a given distance
(public member function) [edit]
advances the iterator by given distance
(public member function) [edit]
(C++11)
decrement an iterator
(function template) [edit]
decrement an iterator by a given distance or to a bound
(niebloid)[edit]