Stack<T> 類別

定義

generic <typename T>
public ref class Stack : System::Collections::Generic::IEnumerable<T>, System::Collections::Generic::IReadOnlyCollection<T>, System::Collections::ICollection

generic <typename T>
public ref class Stack : System::Collections::Generic::IEnumerable<T>, System::Collections::ICollection

public class Stack<T> : System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.ICollection

[System.Runtime.InteropServices.ComVisible(false)]
[System.Serializable]
public class Stack<T> : System.Collections.Generic.IEnumerable<T>, System.Collections.ICollection

[System.Runtime.InteropServices.ComVisible(false)]
[System.Serializable]
public class Stack<T> : System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.ICollection

public class Stack<T> : System.Collections.Generic.IEnumerable<T>, System.Collections.ICollection

type Stack<'T> = class
    interface seq<'T>
    interface IEnumerable
    interface IReadOnlyCollection<'T>
    interface ICollection

[<System.Runtime.InteropServices.ComVisible(false)>]
[<System.Serializable>]
type Stack<'T> = class
    interface seq<'T>
    interface ICollection
    interface IEnumerable

[<System.Runtime.InteropServices.ComVisible(false)>]
[<System.Serializable>]
type Stack<'T> = class
    interface seq<'T>
    interface IEnumerable
    interface ICollection
    interface IReadOnlyCollection<'T>

type Stack<'T> = class
    interface seq<'T>
    interface ICollection
    interface IEnumerable

Public Class Stack(Of T)
Implements ICollection, IEnumerable(Of T), IReadOnlyCollection(Of T)

Public Class Stack(Of T)
Implements ICollection, IEnumerable(Of T)

類型參數

繼承

Object

Stack<T>

屬性

ComVisibleAttribute SerializableAttribute

實作

IEnumerable<T> IReadOnlyCollection<T> ICollection IEnumerable

範例

下列程式代碼範例示範泛型類別的 Stack<T> 數種方法。 此程式代碼範例會建立具有預設容量的字串堆疊，並使用 Push 方法將五個字串推送至堆疊。 會列舉堆疊的專案，而不會變更堆疊的狀態。 方法 Pop 可用來從堆疊取出第一個字串。 方法 Peek 可用來查看堆疊上的下一個專案，然後使用 Pop 方法將其彈出。

方法 ToArray 可用來建立數位，並將堆疊元素複製到其中，然後將數位傳遞至 Stack<T> 採用 IEnumerable<T>的建構函式，並使用反轉元素的順序建立堆疊的複本。 隨即顯示複本的專案。

建立堆疊大小的兩倍陣列，並使用 CopyTo 方法複製陣列元素，從陣列中間開始。 建 Stack<T> 構函式會再次用來建立堆疊的複本，並反轉元素的順序;因此，這三個 Null 元素位於結尾。

方法 Contains 用來顯示字串 「four」 位於堆疊的第一個複本中，之後 Clear 方法會清除複本，而 Count 屬性顯示堆疊是空的。

using System;
using System.Collections.Generic;

class Example
{
    public static void Main()
    {
        Stack<string> numbers = new Stack<string>();
        numbers.Push("one");
        numbers.Push("two");
        numbers.Push("three");
        numbers.Push("four");
        numbers.Push("five");

        // A stack can be enumerated without disturbing its contents.
        foreach( string number in numbers )
        {
            Console.WriteLine(number);
        }

        Console.WriteLine("\nPopping '{0}'", numbers.Pop());
        Console.WriteLine("Peek at next item to destack: {0}",
            numbers.Peek());
        Console.WriteLine("Popping '{0}'", numbers.Pop());

        // Create a copy of the stack, using the ToArray method and the
        // constructor that accepts an IEnumerable<T>.
        Stack<string> stack2 = new Stack<string>(numbers.ToArray());

        Console.WriteLine("\nContents of the first copy:");
        foreach( string number in stack2 )
        {
            Console.WriteLine(number);
        }

        // Create an array twice the size of the stack and copy the
        // elements of the stack, starting at the middle of the
        // array.
        string[] array2 = new string[numbers.Count * 2];
        numbers.CopyTo(array2, numbers.Count);

        // Create a second stack, using the constructor that accepts an
        // IEnumerable(Of T).
        Stack<string> stack3 = new Stack<string>(array2);

        Console.WriteLine("\nContents of the second copy, with duplicates and nulls:");
        foreach( string number in stack3 )
        {
            Console.WriteLine(number);
        }

        Console.WriteLine("\nstack2.Contains(\"four\") = {0}",
            stack2.Contains("four"));

        Console.WriteLine("\nstack2.Clear()");
        stack2.Clear();
        Console.WriteLine("\nstack2.Count = {0}", stack2.Count);
    }
}

/* This code example produces the following output:

five
four
three
two
one

Popping 'five'
Peek at next item to destack: four
Popping 'four'

Contents of the first copy:
one
two
three

Contents of the second copy, with duplicates and nulls:
one
two
three




stack2.Contains("four") = False

stack2.Clear()

stack2.Count = 0
 */

open System
open System.Collections.Generic

let numbers = Stack()
numbers.Push "one"
numbers.Push "two"
numbers.Push "three"
numbers.Push "four"
numbers.Push "five"

// A stack can be enumerated without disturbing its contents.
for number in numbers do
    printfn $"{number}"

printfn $"\nPopping '{numbers.Pop()}'"
printfn $"Peek at next item to destack: {numbers.Peek()}"
numbers.Peek() |> ignore
printfn $"Popping '{numbers.Pop()}'"

// Create a copy of the stack, using the ToArray method and the
// constructor that accepts an IEnumerable<T>.
let stack2 = numbers.ToArray() |> Stack

printfn "\nContents of the first copy:"

for number in stack2 do
    printfn $"{number}"

// Create an array twice the size of the stack and copy the
// elements of the stack, starting at the middle of the
// array.
let array2 = numbers.Count * 2 |> Array.zeroCreate
numbers.CopyTo(array2, numbers.Count)

// Create a second stack, using the constructor that accepts an
// IEnumerable(Of T).
let stack3 = Stack array2

printfn "\nContents of the second copy, with duplicates and nulls:"

for number in stack3 do
    printfn $"{number}"

printfn
    $"""
stack2.Contains "four" = {stack2.Contains "four"}"""

printfn "\nstack2.Clear()"
stack2.Clear()
printfn $"\nstack2.Count = {stack2.Count}"

// This code example produces the following output:
//       five
//       four
//       three
//       two
//       one
//
//       Popping 'five'
//       Peek at next item to destack: four
//       Popping 'four'
//
//       Contents of the first copy:
//       one
//       two
//       three
//
//       Contents of the second copy, with duplicates and nulls:
//       one
//       two
//       three
//
//       stack2.Contains("four") = False
//
//       stack2.Clear()
//
//       stack2.Count = 0

Imports System.Collections.Generic

Module Example

    Sub Main

        Dim numbers As New Stack(Of String)
        numbers.Push("one")
        numbers.Push("two")
        numbers.Push("three")
        numbers.Push("four")
        numbers.Push("five")

        ' A stack can be enumerated without disturbing its contents.
        For Each number As String In numbers
            Console.WriteLine(number)
        Next

        Console.WriteLine(vbLf & "Popping '{0}'", numbers.Pop())
        Console.WriteLine("Peek at next item to pop: {0}", _
            numbers.Peek())    
        Console.WriteLine("Popping '{0}'", numbers.Pop())

        ' Create another stack, using the ToArray method and the
        ' constructor that accepts an IEnumerable(Of T). Note that
        ' the order of items on the new stack is reversed.
        Dim stack2 As New Stack(Of String)(numbers.ToArray())

        Console.WriteLine(vbLf & "Contents of the first copy:")
        For Each number As String In stack2
            Console.WriteLine(number)
        Next
        
        ' Create an array twice the size of the stack, compensating
        ' for the fact that Visual Basic allocates an extra array 
        ' element. Copy the elements of the stack, starting at the
        ' middle of the array. 
        Dim array2((numbers.Count * 2) - 1) As String
        numbers.CopyTo(array2, numbers.Count)
        
        ' Create a second stack, using the constructor that accepts an
        ' IEnumerable(Of T). The elements are reversed, with the null
        ' elements appearing at the end of the stack when enumerated.
        Dim stack3 As New Stack(Of String)(array2)

        Console.WriteLine(vbLf & _
            "Contents of the second copy, with duplicates and nulls:")
        For Each number As String In stack3
            Console.WriteLine(number)
        Next

        Console.WriteLine(vbLf & "stack2.Contains(""four"") = {0}", _
            stack2.Contains("four"))

        Console.WriteLine(vbLf & "stack2.Clear()")
        stack2.Clear()
        Console.WriteLine(vbLf & "stack2.Count = {0}", _
            stack2.Count)
    End Sub
End Module

' This code example produces the following output:
'
'five
'four
'three
'two
'one
'
'Popping 'five'
'Peek at next item to pop: four
'Popping 'four'
'
'Contents of the first copy:
'one
'two
'three
'
'Contents of the second copy, with duplicates and nulls:
'one
'two
'three
'
'
'
'
'stack2.Contains("four") = False
'
'stack2.Clear()
'
'stack2.Count = 0

備註

Stack<T> 會實作為陣列。

當您需要暫存記憶體以取得資訊時，堆疊和佇列很有用;也就是說，當您想要在擷取元素的值之後捨棄專案時。 如果您需要以儲存在集合中的相同順序存取資訊，請使用 Queue<T> 。 如果您需要以反向順序存取資訊，請使用 System.Collections.Generic.Stack<T> 。

System.Collections.Concurrent.ConcurrentStack<T>當您需要同時從多個線程存取集合時，請使用和 System.Collections.Concurrent.ConcurrentQueue<T> 類型。

的常見用途 System.Collections.Generic.Stack<T> 是在呼叫其他程序期間保留變數狀態。

您可以在 及其元素上 System.Collections.Generic.Stack<T> 執行三個主要作業：

• Push 在頂端 Stack<T>插入專案。

• Pop 從頂 Stack<T>端移除 專案。

• Peek 傳回位於 頂端但 Stack<T> 不會從 Stack<T>移除的專案。

的 Stack<T> 容量是 可以保留的項目 Stack<T> 數目。 當元素新增至 Stack<T>時，重新配置內部數位會自動增加容量。 您可以藉由呼叫 TrimExcess來減少容量。

如果 Count 小於堆疊的容量， Push 則 為 O (1) 作業。 如果需要增加容量以容納新元素， Push 會變成 O (n) 作業，其中 n 是 Count。 Pop 是 O (1) 作業。

Stack<T> 接受 null 作為參考型別的有效值，並允許重複的專案。

建構函式

屬性

方法

明確介面實作

擴充方法

適用於

執行緒安全性

Visual Basic 中的公用靜態 (Shared) 此類型的成員是安全線程。 並非所有的執行個體成員都是安全執行緒。

Stack<T>可以同時支援多個讀取器，只要集合未修改即可。 即使如此，透過集合列舉本質上不是安全線程的程式。 若要確保列舉期間的執行緒安全性，您可以在整個列舉期間鎖定集合。 若要讓多重執行緒能夠存取集合以便進行讀取和寫入，您必須實作自己的同步處理。

另請參閱

• 迭代器 (C#)
• 迭代器 (Visual Basic)