Programming C# 3.0, 5th 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. An item added on top is the first item 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. Table 9-5 shows the significant methods and properties for Stack.

Table 9-5. Stack methods and properties

Method or property	Purpose
Count	Public property that gets the number of elements in the Stack
Clear( )	Removes all objects from the Stack
Contains( )	Determines whether 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
TrimExcess( )	If the number of elements in the current stack is less than 90 percent of its capacity, reduces the current stack's capacity to the actual number of elements in the stack

The List, Queue, and Stack types contain overloaded CopyTo( ) and ToArray( ) methods for copying their elements to an array. In the case of a Stack, the CopyTo( ) method will copy its elements to an existing one-dimensional array, overwriting the contents of the array beginning at the index you specify. The ToArray( ) method returns a new array ...