queue functions code example

Example 1: stl queue

Functions used here:
   q.size() = Returns the size of queue.
   q.push() = It is used to insert elements to the queue.
   q.pop() = To pop out the value from the queue.
   q.front() = Returns the front element of the array.
   q.back() = Returns the back element of the array.

Example 2: queue

Quque: accepts duplicates, does not have index,
First in first out order