C# 0 The Complete Reference

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.

Method

Description

public vir tual void Clear( )

Sets 

Count

 to zero, which effectively clears 

the stack.

public vir tual bool Contains(object 

v

)

Returns true if 

v

 is on the invoking stack. If 

v

is not found, false is returned.

public vir tual object Peek( )

Returns the element on the top of the stack, 

but does not remove it.

public vir tual object Pop( )

Returns the element on the top of the stack, 

removing it in the process.

public vir tual void Push(object 

v

)

Pushes 

v

 onto the stack. 

public static Stack Synchronized(Stack 

stk

)

Returns a synchronized version of the 

Stack

passed in 

stk.

public vir tual object[ ] ToArray( )

Returns an array that contains copies of the 

elements of the invoking stack.

T

ABLE

 24-7 

The Methods Defi ned by 

Stack

www.freepdf-books.com

---

768

 

P a r t   I I :  

E x p l o r i n g   t h e   C #   L i b r a r y

Here is an example that creates a stack, pushes several integers onto it, and then pops 

them off again:

// Demonstrate the Stack class.

using System;

using System.Collections;

class StackDemo {

  static void ShowPush(Stack st, int a) {

    st.Push(a);

    Console.WriteLine("Push(" + a + ")");

    Console.Write("stack: ");

    foreach(int i in st)

      Console.Write(i + " ");

    Console.WriteLine();

  }

  static void ShowPop(Stack st) {

    Console.Write("Pop -> ");

    int a = (int) st.Pop();

    Console.WriteLine(a);

    Console.Write("stack: ");

    foreach(int i in st)

      Console.Write(i + " ");

    Console.WriteLine();

  }

  static void Main() {

    Stack st = new Stack();

    foreach(int i in st)

      Console.Write(i + " ");

    Console.WriteLine();

    ShowPush(st, 22);

    ShowPush(st, 65);

    ShowPush(st, 91);

    ShowPop(st);

    ShowPop(st);

    ShowPop(st);

    try {

      ShowPop(st);

    } catch (InvalidOperationException) {

      Console.WriteLine("Stack empty.");

www.freepdf-books.com

---