std::ranges::subrange<I,S,K>::prev
From cppreference.com
C++
Ranges library
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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;
Parameters
| n | - | number of decrements of the iterator |
Return value
As described above.
Notes
The difference between this function and advance() is that the latter performs the decrement (or increment) in place.
Example
Run this code
#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]
See also
obtains a copy of the subrange with its iterator advanced by a given distance (public member function) |
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| advances the iterator by given distance (public member function) |
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(C++11)
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decrement an iterator (function template) |
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(C++20)
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decrement an iterator by a given distance or to a bound (algorithm function object) |