Programming C#, Second Edition

Stacks

A stack is a last-in, first-out (LIFO) collection, like a stack of dishes at a buffet table, or a stack of coins on your desk. Add a dish on top, which is the first dish you take off the stack.

The principal methods for adding to and removing from a stack are Push and Pop( ) ; Stack also offers a Peek( ) method, very much like Queue. The significant methods and properties for Stack are shown in Table 9-5.

Table 9-5. Stack methods and properties

Method or property	Purpose
Synchronized( )	Public static method that returns a thread-safe Stack wrapper.
Count	Public property that gets the number of elements in the Stack.
IsSynchronized	Public property that gets a value indicating if the Stack is synchronized.
SyncRoot	Public property that returns an object that can be used to synchronize access to the Stack.
Clear( )	Removes all objects from the Stack.
Clone( )	Creates a shallow copy.
Contains( )	Determines if an element is in the Stack.
CopyTo( )	Copies the Stack elements to an existing one-dimensional array.
GetEnumerator( )	Returns an enumerator for the Stack.
Peek( )	Returns the object at the top of the Stack without removing it.
Pop( )	Removes and returns the object at the top of the Stack.
Push( )	Inserts an object at the top of the Stack.
ToArray( )	Copies the elements to a new array.

The ArrayList, Queue, and Stack types contain overloaded CopyTo( ) and ToArray( ) methods for copying their elements to an array. In the ...