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Difference between revisions of "cpp/container/priority queue/pop"

From cppreference.com
m (r2.7.3) (Robot: Adding de, es, fr, it, pt, zh)
m (Shorten template names. Use {{lc}} where appropriate.)
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{{page template|cpp/container/pop|priority_queue}}
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{{include page|cpp/container/pop|priority_queue}}
  
 
[[de:cpp/container/priority queue/pop]]
 
[[de:cpp/container/priority queue/pop]]

Revision as of 19:34, 31 May 2013

 
 
 
 
void pop();

Removes the top element from the priority queue. Effectively calls std::pop_heap(c.begin(), c.end(), comp); c.pop_back();.

Contents

Parameters

(none)

Return value

(none)

Complexity

Logarithmic number of comparisons plus the complexity of Container::pop_back.

Example

#include <iostream>
#include <queue>
 
struct Event
{
    int priority{};
    char data{' '};
 
    friend bool operator<(Event const& lhs, Event const& rhs)
    {
        return lhs.priority < rhs.priority;
    }
 
    friend std::ostream& operator<<(std::ostream& os, Event const& e)
    {
        return os << '{' << e.priority << ", '" << e.data << "'}";
    }
};
 
int main()
{
    std::priority_queue<Event> events;
 
    std::cout << "Fill the events queue:\t";
 
    for (auto const e : {Event{6,'L'}, {8,'I'}, {9,'S'}, {1,'T'}, {5,'E'}, {3,'N'}})
    {
        std::cout << e << ' ';
        events.push(e);
    }
 
    std::cout << "\nProcess events:\t\t";
 
    for (; !events.empty(); events.pop())
    {
        Event const& e = events.top();
        std::cout << e << ' ';
    }
 
    std::cout << '\n';
}

Output:

Fill the events queue:  {6, 'L'} {8, 'I'} {9, 'S'} {1, 'T'} {5, 'E'} {3, 'N'}
Process events:         {9, 'S'} {8, 'I'} {6, 'L'} {5, 'E'} {3, 'N'} {1, 'T'}

See also

(C++11)
constructs element in-place and sorts the underlying container
(public member function) [edit]
inserts element and sorts the underlying container
(public member function) [edit]
accesses the top element
(public member function) [edit]