public member function
<queue>
std::queue::empty
Test whether container is empty
Returns whether the queue is empty: i.e. whether its size is zero.
This member function effectively calls member empty of the underlying container object.
Return Value
true if the underlying container's size is 0, false otherwise.
Example
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// queue::empty
#include <iostream> // std::cout
#include <queue> // std::queue
int main ()
{
std::queue<int> myqueue;
int sum (0);
for (int i=1;i<=10;i++) myqueue.push(i);
while (!myqueue.empty())
{
sum += myqueue.front();
myqueue.pop();
}
std::cout << "total: " << sum << '\n';
return 0;
}
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The example initializes the content of the queue to a sequence of numbers (form 1 to 10). It then pops the elements one by one until it is empty and calculates their sum.
Output:
Complexity
Constant (calling empty on the underlying container).
Data races
The container is accessed.
Exception safety
Provides the same level of guarantees as the operation performed on the container (no-throw guarantee for standard container types).
See also
- queue::size
- Return size (public member function)