C# 0 The Complete Reference

The Stack Class

Stack

is the generic equivalent of the non-generic 

Stack

 class. 

Stack

 supports a 

first-in, last-out stack. It implements the 

ICollection

,

IEnumerable

, and 

IEnumerable

interfaces.

Stack

 directly implements the 

Clear( )

,

Contains( )

, and 

CopyTo( )

 methods 

defined by 

ICollection

. (The 

Add( ) 

and

Remove( )

 methods are not supported, nor is 

the

IsReadOnly

 property.) 

Stack

 is a dynamic collection that grows as needed to 

accommodate the elements it must store. It defines the following constructors:

public Stack( )

public Stack(int 

capacity

)

public Stack(IEnumerable 

c

)

The first form creates an empty stack with a default initial capacity. The second form creates 

an empty stack with the initial capacity specified by 

capacity.

 The third form creates a stack 

that contains the elements of the collection specified by 

c.

In addition to the methods defined by the interfaces that it implements (and those 

methods defined by 

ICollection

 that it implements on its own), 

Stack

 defines the 

methods shown in Table 24-19. 

Stack

 works just like its non-generic counterpart. To put an 

object on the top of the stack, call 

Push( )

. To remove and return the top element, call 

Pop( )

.

You can use 

Peek( )

 to return, but not remove, the top object. An 

InvalidOperationException

is thrown if you call 

Pop( )

 or 

Peek( )

 when the invoking stack is empty.

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