std::stable_sort
Defined in header <algorithm>
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template< class RandomIt > void stable_sort( RandomIt first, RandomIt last ); |
(1) | |
template< class ExecutionPolicy, class RandomIt > void stable_sort( ExecutionPolicy&& policy, RandomIt first, RandomIt last ); |
(2) | (since C++17) |
template< class RandomIt, class Compare > void stable_sort( RandomIt first, RandomIt last, Compare comp ); |
(3) | |
template< class ExecutionPolicy, class RandomIt, class Compare > void stable_sort( ExecutionPolicy&& policy, RandomIt first, RandomIt last, Compare comp ); |
(4) | (since C++17) |
Sorts the elements in the range [first, last)
in ascending order. The order of equivalent elements is guaranteed to be preserved.
operator<
.comp
.policy
. These overloads do not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is trueParameters
first, last | - | the range of elements to sort |
policy | - | the execution policy to use. See execution policy for details. |
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); While the signature does not need to have const &, the function must not modify the objects passed to it and must be able to accept all values of type (possibly const) |
Type requirements | ||
-RandomIt must meet the requirements of ValueSwappable and LegacyRandomAccessIterator.
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-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible.
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Return value
(none)
Complexity
O(N·log(N)2), where N = std::distance(first, last) applications of cmp
. If additional memory is available, then the complexity is O(N·log(N)).
Exceptions
The overloads with a template parameter named ExecutionPolicy
report errors as follows:
- If execution of a function invoked as part of the algorithm throws an exception and
ExecutionPolicy
is one of the standard policies, std::terminate is called. For any otherExecutionPolicy
, the behavior is implementation-defined. - If the algorithm fails to allocate memory, std::bad_alloc is thrown.
Notes
This function attempts to allocate a temporary buffer equal in size to the sequence to be sorted. If the allocation fails, the less efficient algorithm is chosen.
Example
#include <algorithm> #include <iostream> #include <string> #include <vector> struct Employee { int age; std::string name; // Does not participate in comparisons }; bool operator<(const Employee & lhs, const Employee & rhs) { return lhs.age < rhs.age; } int main() { std::vector<Employee> v = { {108, "Zaphod"}, {32, "Arthur"}, {108, "Ford"}, }; std::stable_sort(v.begin(), v.end()); for (const Employee & e : v) std::cout << e.age << ", " << e.name << '\n'; }
Output:
32, Arthur 108, Zaphod 108, Ford
See also
sorts the first N elements of a range (function template) | |
sorts a range into ascending order (function template) |