Stack<T> 类

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)

继承

Object

Stack<T>

属性

ComVisibleAttribute SerializableAttribute

实现

IEnumerable<T> IReadOnlyCollection<T> ICollection IEnumerable

下面的代码示例演示 Stack<T> 泛型类的几种方法。 该代码示例创建一个具有默认容量的字符串堆栈，并使用 Push 方法将五个字符串推送到堆栈上。 枚举堆栈的元素，不会更改堆栈的状态。 Pop 方法用于从堆栈中弹出第一个字符串。 Peek 方法用于查看堆栈上的下一项，然后使用 Pop 方法将其弹出。

ToArray 方法用于创建数组并将堆栈元素复制到该数组，然后将该数组传递给采用 IEnumerable<T>的 Stack<T> 构造函数，并创建堆栈的副本，并按元素的顺序反转。 将显示副本的元素。

创建堆栈大小的数组两次，CopyTo 方法用于复制数组元素，从数组中间开始。 Stack<T> 构造函数再次用于创建堆栈的副本，并反转元素的顺序;因此，这三个 null 元素位于末尾。

Contains 方法用于显示字符串“four”位于堆栈的第一个副本中，之后 Clear 方法清除副本，Count 属性显示堆栈为空。

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

Stack<T> 作为数组实现。

需要临时存储以获取信息时，堆栈和队列非常有用;也就是说，在检索元素值后可能要放弃该元素时。 如果需要按照存储在集合中的相同顺序访问信息，请使用 Queue<T>。 如果需要按相反顺序访问信息，请使用 System.Collections.Generic.Stack<T>。

如果需要同时从多个线程访问集合，请使用 System.Collections.Concurrent.ConcurrentStack<T> 和 System.Collections.Concurrent.ConcurrentQueue<T> 类型。

System.Collections.Generic.Stack<T> 的常见用途是在调用其他过程期间保留变量状态。

可以对 System.Collections.Generic.Stack<T> 及其元素执行三个主要操作：

• Push 在 Stack<T>顶部插入元素。

• Pop 从 Stack<T>顶部删除元素。

• Peek 返回位于 Stack<T> 顶部但不会将其从 Stack<T>中删除的元素。

Stack<T> 的容量是 Stack<T> 可以保留的元素数。 随着元素添加到 Stack<T>，重新分配内部数组，容量会根据需要自动增加。 可以通过调用 TrimExcess来减少容量。

如果 Count 小于堆栈的容量，Push 为 O（1） 操作。 如果需要增加容量以容纳新元素，Push 将成为 O（n） 操作，其中 nCount。 Pop 是 O（1） 操作。

Stack<T> 接受 null 作为引用类型的有效值，并允许重复元素。

此类型的公共静态（Shared）成员是线程安全的。 不保证任何实例成员都是线程安全的。

只要集合未修改，Stack<T> 就可以同时支持多个读取器。 即便如此，通过集合进行枚举本质上不是线程安全的过程。 若要保证枚举期间的线程安全性，可以在整个枚举期间锁定集合。 若要允许多个线程访问集合进行读取和写入，必须实现自己的同步。

• 迭代器 （C#）
• 迭代器 （Visual Basic）