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C++ Queue Library - back() Function
Description
The C++ function std::queue::back() returns a reference to the last element of queue. This is the most recently enqueued element.
Declaration
Following is the declaration for std::queue::back() function form std::queue header.
C++98
value_type& back(); const value_type& back() const;
C++11
reference& back(); const_reference& back() const;
Parameters
None
Return value
Returns reference to the last element of the queue.
Exceptions
No-throw guarantee for standard non-empty containers.
Time complexity
Constant i.e. O(1)
Example
The following example shows the usage of std::queue::back() function.
#include <iostream> #include <queue> using namespace std; int main(void) { queue<int> q; for (int i = 0; i < 5; ++i) q.push(i + 1); cout << "Last element of queue q is = " << q.back() << endl; return 0; }
Let us compile and run the above program, this will produce the following result −
Last element of queue q is = 5
queue.htm
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