(C++17) | ||||
| Sequence | ||||
(C++11) | ||||
(C++26) | ||||
(C++26) | ||||
(C++11) | ||||
| Associative | ||||
| Unordered associative | ||||
(C++11) | ||||
(C++11) | ||||
(C++11) | ||||
(C++11) | ||||
| Adaptors | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
| Views | ||||
(C++20) | ||||
(C++23) | ||||
| Tables | ||||
| Iterator invalidation | ||||
| Member function table | ||||
| Non-member function table |
std::queue| Member functions | ||||
| Element access | ||||
| Capacity | ||||
queue::empty | ||||
| Modifiers | ||||
(C++23) | ||||
(C++11) | ||||
(C++11) | ||||
| Non-member functions | ||||
(C++11) | ||||
| Helper classes | ||||
(C++11) | ||||
(C++23) | ||||
| Deduction guides(C++17) |
bool empty()const; | ||
Checks if the underlying container has no elements. Equivalent to:return c.empty().
Contents |
(none)
true if the underlying container is empty,false otherwise.
Constant.
#include <cassert>#include <queue> int main(){std::queue<int> queue;assert(queue.empty()); queue.push(42);assert(!queue.empty()); queue.pop();assert(queue.empty());}
| returns the number of elements (public member function)[edit] | |
(C++17) | checks whether the container is empty (function template)[edit] |
