priority_queue() : priority_queue(Compare(), Container()) { } | (1) | (since C++11) |
explicit priority_queue( const Compare& compare ) : priority_queue(compare, Container()) { } | (2) | (since C++11) |
(3) | ||
explicit priority_queue( const Compare& compare = Compare(), const Container& cont = Container() ); | (until C++11) | |
priority_queue( const Compare& compare, const Container& cont ); | (since C++11) | |
priority_queue( const Compare& compare, Container&& cont ); | (4) | (since C++11) |
priority_queue( const priority_queue& other ); | (5) | |
priority_queue( priority_queue&& other ); | (6) | (since C++11) |
template< class InputIt > priority_queue( InputIt first, InputIt last, const Compare& compare = Compare() ); | (7) | (since C++11) |
(8) | ||
template< class InputIt > priority_queue( InputIt first, InputIt last, const Compare& compare = Compare(), const Container& cont = Container() ); | (until C++11) | |
template< class InputIt > priority_queue( InputIt first, InputIt last, const Compare& compare, const Container& cont ); | (since C++11) | |
template< class InputIt > priority_queue( InputIt first, InputIt last, const Compare& compare, Container&& cont ); | (9) | (since C++11) |
template< class Alloc > explicit priority_queue( const Alloc& alloc ); | (10) | (since C++11) |
template< class Alloc > priority_queue( const Compare& compare, const Alloc& alloc ); | (11) | (since C++11) |
template< class Alloc > priority_queue( const Compare& compare, const Container& cont, const Alloc& alloc ); | (12) | (since C++11) |
template< class Alloc > priority_queue( const Compare& compare, Container&& cont, const Alloc& alloc ); | (13) | (since C++11) |
template< class Alloc > priority_queue( const priority_queue& other, const Alloc& alloc ); | (14) | (since C++11) |
template< class Alloc > priority_queue( priority_queue&& other, const Alloc& alloc ); | (15) | (since C++11) |
template< class InputIt, class Alloc > priority_queue( InputIt first, InputIt last, const Alloc& alloc ); | (16) | (since C++11) |
template< class InputIt, class Alloc > priority_queue( InputIt first, InputIt last, const Compare& compare, const Alloc& alloc ); | (17) | (since C++11) |
template< class InputIt, class Alloc > priority_queue( InputIt first, InputIt last, const Compare& compare, const Container& cont, const Alloc& alloc ); | (18) | (since C++11) |
template< class InputIt, class Alloc > priority_queue( InputIt first, InputIt last, const Compare& compare, Container&& cont, const Alloc& alloc ); | (19) | (since C++11) |
template< container-compatible-range<T> R > priority_queue( std::from_range_t, R&& rg, const Compare& compare = Compare() ); | (20) | (since C++23) |
template< container-compatible-range<T> R, class Alloc > priority_queue( std::from_range_t, R&& rg, const Compare& compare, const Alloc& alloc ); | (21) | (since C++23) |
template< container-compatible-range<T> R, class Alloc > priority_queue( std::from_range_t, R&& rg, const Alloc& alloc ); | (22) | (since C++23) |
Constructs new underlying container of the container adaptor from a variety of data sources.
comp
with the contents of compare
. Value-initializes the underlying container c
.c
with the contents of cont
. Copy-constructs the comparison functor comp
with the contents of compare
. Calls std::make_heap(c.begin(), c.end(), comp)
. This is also the default constructor. (until C++11)
c
with std::move(cont)
. Copy-constructs the comparison functor comp
with compare
. Calls std::make_heap(c.begin(), c.end(), comp)
.other.c
. The comparison functor is copy-constructed with other.comp
. (implicitly declared)
std::move(other.c)
.The comparison functor is constructed with std::move(other.comp)
. (implicitly declared)
InputIt
satisfies LegacyInputIterator.c
as if by c(first, last)
and comp
from compare
. Then calls std::make_heap(c.begin(), c.end(), comp);
.c
from cont
and comp
from compare
. Then calls c.insert(c.end(), first, last);
, and then calls std::make_heap(c.begin(), c.end(), comp);
.c
from std::move(cont)
and copy-constructs comp
from compare
. Then calls c.insert(c.end(), first, last);
, and then calls std::make_heap(c.begin(), c.end(), comp);
.std::uses_allocator<container_type, Alloc>::value
is true
, that is, if the underlying container is an allocator-aware container (true for all standard library containers).alloc
as allocator. Effectively calls c(alloc)
. comp
is value-initialized.alloc
as allocator. Effectively calls c(alloc)
. Copy-constructs comp
from compare
.cont
and using alloc
as allocator, as if by c(cont, alloc)
. Copy-constructs comp
from compare
. Then calls std::make_heap(c.begin(), c.end(), comp)
.cont
using move semantics while using alloc
as allocator, as if by c(std::move(cont), alloc)
. Copy-constructs comp
from compare
. Then calls std::make_heap(c.begin(), c.end(), comp)
.other.c
and using alloc
as allocator. Effectively calls c(other.c, alloc)
. Copy-constructs comp
from other.comp
.other
using move semantics while utilizing alloc
as allocator. Effectively calls c(std::move(other.c), alloc)
. Move-constructs comp
from other.comp
.alloc
is used for constructing the underlying container. These overloads participate in overload resolution only if std::uses_allocator<container_type, Alloc>::value
is true
and InputIt
satisfies LegacyInputIterator.comp
with compare
and c
with ranges::to<Container>(std::forward<R>(rg))
. Then calls std::make_heap(c.begin(), c.end(), comp)
.comp
with compare
and c
with ranges::to<Container>(std::forward<R>(rg), alloc)
. Then calls std::make_heap(c.begin(), c.end(), comp)
. c
with ranges::to<Container>(std::forward<R>(rg), alloc)
. Then calls std::make_heap(c.begin(), c.end(), comp)
.Note that how an implementation checks whether a type satisfies LegacyInputIterator is unspecified, except that integral types are required to be rejected.
alloc | - | allocator to use for all memory allocations of the underlying container |
other | - | another container adaptor to be used as source to initialize the underlying container |
cont | - | container to be used as source to initialize the underlying container |
compare | - | the comparison function object to initialize the underlying comparison functor |
first, last | - | a range [ first , last ) of elements to initialize with |
rg | - | a container compatible range, that is, an input_range whose elements are convertible to T |
Type requirements | ||
-Alloc must meet the requirements of Allocator. |
||
-Compare must meet the requirements of Compare. |
||
-Container must meet the requirements of Container. The allocator-extended constructors are only defined if Container meets the requirements of AllocatorAwareContainer. |
||
-InputIt must meet the requirements of LegacyInputIterator. |
value_type
, where \(\scriptsize N\)N is cont.size()
.cont.size()
.std::distance(first, last)
.value_type
, where \(\scriptsize N\)N is cont.size()
and \(\scriptsize M\)M is std::distance(first, last)
.cont.size()
and \(\scriptsize M\)M is std::distance(first, last)
.cont.size()
.other
.Alloc
compares equal to the allocator of other
. Linear in size of other
otherwise.value_type
(present if Alloc
does not compare equal to the allocator of other
), where \(\scriptsize N\)N is cont.size()
and \(\scriptsize M\)M is std::distance(first, last)
.value_type
, where \(\scriptsize N\)N is ranges::distance(rg)
.Feature-test macro | Value | Std | Comment |
---|---|---|---|
__cpp_lib_containers_ranges | 202202L | (C++23) | Ranges-aware construction and insertion; overloads (20-22) |
#include <complex> #include <functional> #include <iostream> #include <queue> #include <vector> int main() { std::priority_queue<int> pq1; pq1.push(5); std::cout << "pq1.size() = " << pq1.size() << '\n'; std::priority_queue<int> pq2 {pq1}; std::cout << "pq2.size() = " << pq2.size() << '\n'; std::vector<int> vec {3, 1, 4, 1, 5}; std::priority_queue<int> pq3 {std::less<int>(), vec}; std::cout << "pq3.size() = " << pq3.size() << '\n'; for (std::cout << "pq3 : "; !pq3.empty(); pq3.pop()) std::cout << pq3.top() << ' '; std::cout << '\n'; // Demo With Custom Comparator: using my_value_t = std::complex<double>; using my_container_t = std::vector<my_value_t>; auto my_comp = [](const my_value_t& z1, const my_value_t& z2) { return z2.real() < z1.real(); }; std::priority_queue<my_value_t, my_container_t, decltype(my_comp)> pq4 {my_comp}; using namespace std::complex_literals; pq4.push(5.0 + 1i); pq4.push(3.0 + 2i); pq4.push(7.0 + 3i); for (; !pq4.empty(); pq4.pop()) { const auto& z = pq4.top(); std::cout << "pq4.top() = " << z << '\n'; } // TODO: C++23 range-aware ctors }
Output:
pq1.size() = 1 pq2.size() = 1 pq3.size() = 5 pq3 : 5 4 3 1 1 pq4.top() = (3,2) pq4.top() = (5,1) pq4.top() = (7,3)
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
P0935R0 | C++11 | default constructor and constructor (4) were explicit | made implicit |
LWG 3506 | C++11 | allocator-extended iterator-pair constructors were missing | added |
LWG 3522 | C++11 | constraints on iterator-pair constructors were missing | added |
LWG 3529 | C++11 | construction from a pair of iterators called insert | constructs the container from them |
assigns values to the container adaptor (public member function) |
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