From cppreference.com
size_typesize()const;Returns the number of elements in the container adaptor. Equivalent to: return
.size().
Return value
The number of elements in the container adaptor.
Complexity
Constant.
Example
Run this code
#include<cassert>#include<queue>intmain(){std::queue<int>queue;assert(queue.size()==0);constintcount=8;for(inti=0;i!=count;++i)queue.push(i);assert(queue.size()==count);}See also
checks whether the container adaptor is empty
(public member function)
(C++17)(C++20)
returns the size of a container or array
(function template)