Difference between revisions of "cpp/container/priority queue/emplace"
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< cpp | container | priority queue
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Latest revision as of 23:57, 30 August 2021
| template< class... Args > void emplace( Args&&... args ); |
(since C++11) | |
Pushes a new element to the priority queue. The element is constructed in-place, i.e. no copy or move operations are performed. The constructor of the element is called with exactly the same arguments as supplied to the function.
Effectively callsc.emplace_back(std::forward<Args>(args)...); std::push_heap(c.begin(), c.end(), comp);
Contents |
[edit] Parameters
| args | - | arguments to forward to the constructor of the element |
[edit] Return value
(none)
[edit] Complexity
Logarithmic number of comparisons plus the complexity of Container::emplace_back.
[edit] Example
Run this code
#include <iostream> #include <queue> struct S { int id; S(int i, double d, std::string s) : id{i} { std::cout << "S::S(" << i << ", " << d << ", \"" << s << "\");\n"; } friend bool operator< (S const& x, S const& y) { return x.id < y.id; } }; int main() { std::priority_queue<S> queue; queue.emplace(42, 3.14, "C++"); std::cout << "id: " << queue.top().id << '\n'; }
Output:
S::S(42, 3.14, "C++") id = 42
[edit] See also
| inserts element and sorts the underlying container (public member function) | |
| removes the top element (public member function) |
