std::is_sorted
From cppreference.com
Defined in header
<algorithm>
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template< class ForwardIt >
bool is_sorted( ForwardIt first, ForwardIt last ); |
(1) | (since C++11) |
template< class ForwardIt, class Compare >
bool is_sorted( ForwardIt first, ForwardIt last, Compare comp ); |
(2) | (since C++11) |
Checks if the elements in range [first, last)
are sorted in ascending order. The first version of the function uses operator< to compare the elements, the second uses the given comparison function comp
.
Contents |
[edit] Parameters
first, last | - | the range of elements to examine |
comp | - | comparison function object (i.e. an object that satisfies the requirements of Compare ) which returns true if the first argument is less than (i.e. is ordered before) the second. The signature of the comparison function should be equivalent to the following: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function object must not modify the objects passed to it. |
Type requirements | ||
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ForwardIt must meet the requirements of ForwardIterator .
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[edit] Return value
true if the elements in the range are sorted in ascending order
[edit] Complexity
linear in the distance between first
and last
[edit] Possible implementation
First version |
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template<class ForwardIt> bool is_sorted(ForwardIt first, ForwardIt last) { return std::is_sorted_until(first, last) == last; } |
Second version |
template<class ForwardIt, class Compare> bool is_sorted(ForwardIt first, ForwardIt last, Compare comp) { return std::is_sorted_until(first, last, comp) == last; } |
[edit] Example
Run this code
#include <iostream> #include <algorithm> int main() { const int N = 5; int digits[N] = {3, 1, 4, 1, 5}; for (auto i : digits) std::cout << i << ' '; std::cout << ": is_sorted: " << std::is_sorted(digits, digits+N) << '\n'; std::sort(digits, digits+N); for (auto i : digits) std::cout << i << ' '; std::cout << ": is_sorted: " << std::is_sorted(digits, digits+N) << '\n'; }
Output:
3 1 4 1 5 : is_sorted: 0 1 1 3 4 5 : is_sorted: 1
[edit] See also
(C++11)
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finds the largest sorted subrange (function template) |
(parallelism TS)
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parallelized version of std::is_sorted (function template) |