Stack.Pop Method

public:
 virtual System::Object ^ Pop();

public virtual object Pop();

public virtual object? Pop();

abstract member Pop : unit -> obj
override this.Pop : unit -> obj

Public Overridable Function Pop () As Object

Returns

The Object removed from the top of the Stack.

Exceptions

Examples

The following example shows how to add elements to the Stack, remove elements from the Stack, or view the element at the top of the Stack.

using System;
using System.Collections;
public class SamplesStack {

 public static void Main() {

 // Creates and initializes a new Stack.
 Stack myStack = new Stack();
 myStack.Push( "The" );
 myStack.Push( "quick" );
 myStack.Push( "brown" );
 myStack.Push( "fox" );

 // Displays the Stack.
 Console.Write( "Stack values:" );
 PrintValues( myStack, '\t' );

 // Removes an element from the Stack.
 Console.WriteLine( "(Pop)\t\t{0}", myStack.Pop() );

 // Displays the Stack.
 Console.Write( "Stack values:" );
 PrintValues( myStack, '\t' );

 // Removes another element from the Stack.
 Console.WriteLine( "(Pop)\t\t{0}", myStack.Pop() );

 // Displays the Stack.
 Console.Write( "Stack values:" );
 PrintValues( myStack, '\t' );

 // Views the first element in the Stack but does not remove it.
 Console.WriteLine( "(Peek)\t\t{0}", myStack.Peek() );

 // Displays the Stack.
 Console.Write( "Stack values:" );
 PrintValues( myStack, '\t' );
 }

 public static void PrintValues( IEnumerable myCollection, char mySeparator ) {
 foreach ( Object obj in myCollection )
 Console.Write( "{0}{1}", mySeparator, obj );
 Console.WriteLine();
 }
}


/*
This code produces the following output.

Stack values: fox brown quick The
(Pop) fox
Stack values: brown quick The
(Pop) brown
Stack values: quick The
(Peek) quick
Stack values: quick The
*/

Imports System.Collections

Public Class SamplesStack 

 Public Shared Sub Main()

 ' Creates and initializes a new Stack.
 Dim myStack As New Stack()
 myStack.Push("The")
 myStack.Push("quick")
 myStack.Push("brown")
 myStack.Push("fox")

 ' Displays the Stack.
 Console.Write("Stack values:")
 PrintValues(myStack, ControlChars.Tab)

 ' Removes an element from the Stack.
 Console.WriteLine("(Pop)" & ControlChars.Tab & ControlChars.Tab & _
 "{0}", myStack.Pop())

 ' Displays the Stack.
 Console.Write("Stack values:")
 PrintValues(myStack, ControlChars.Tab)

 ' Removes another element from the Stack.
 Console.WriteLine("(Pop)" & ControlChars.Tab & ControlChars.Tab & _
 "{0}", myStack.Pop())

 ' Displays the Stack.
 Console.Write("Stack values:")
 PrintValues(myStack, ControlChars.Tab)

 ' Views the first element in the Stack but does not remove it.
 Console.WriteLine("(Peek)" & ControlChars.Tab & ControlChars.Tab & _
 "{0}", myStack.Peek())

 ' Displays the Stack.
 Console.Write("Stack values:")
 PrintValues(myStack, ControlChars.Tab)

 End Sub

 Public Shared Sub PrintValues(myCollection As IEnumerable, mySeparator As Char)
 Dim obj As [Object]
 For Each obj In myCollection
 Console.Write("{0}{1}", mySeparator, obj)
 Next obj
 Console.WriteLine()
 End Sub

End Class


' This code produces the following output.
' 
' Stack values: fox brown quick The
' (Pop) fox
' Stack values: brown quick The
' (Pop) brown
' Stack values: quick The
' (Peek) quick
' Stack values: quick The

Remarks

This method is similar to the Peek method, but Peek does not modify the Stack.

null can be pushed onto the Stack as a placeholder, if needed. To distinguish between a null value and the end of the stack, check the Count property or catch the InvalidOperationException, which is thrown when the Stack is empty.

This method is an O(1) operation.

See also

• Peek()
• Push(Object)