Queue represents a first-in, first out collection of object. It is used when you need a first-in, first-out access of items. When you add an item in the list, it is called enqueue, and when you remove an item, it is called deque. Queue
- Enqueue adds an element to the end of the Queue.
- Dequeue removes the oldest element from the start of the Queue.
- Peek returns the oldest element that is at the start of the Queue but does not remove it from the Queue.
- The capacity of a Queue is the number of elements the Queue can hold.
- As elements are added to a Queue, the capacity is automatically increased as required by reallocating the internal array.
- Queue accepts null as a valid value for reference types and allows duplicate elements.
Return Value : The Peek() method always returns the first item from a queue collection without removing it from the queue. Calling Peek() and Dequeue() methods on an empty queue collection will throw a run time exception “InvalidOperationException”.
Below given are some examples to understand the implementation in a better way:
Total number of elements in the Queue are : 6 Element at the beginning is : 1st Element Element at the beginning is : 1st Element Total number of elements in the Queue are : 6
System.InvalidOperationException: Queue empty.