共用方式為

Stack<T> 建構函式

  • 參考

定義

命名空間:
System.Collections.Generic
組件:
System.Collections.dll
組件:
System.dll
組件:
netstandard.dll

初始化 Stack<T> 類別的新執行個體。

多載

Stack<T>()

初始化 Stack<T> 類別的新執行個體，這個執行個體為空白且具有預設的初始容量。
Stack<T>(IEnumerable<T>)

初始化 Stack<T> 類別的新執行個體，其包含從指定之集合複製的項目，且具有容納複製之項目數目的足夠容量。
Stack<T>(Int32)

初始化 Stack<T> 類別的新執行個體，其為空白且具有指定的初始容量或預設的初始容量 (兩者中較大的那一個)。

Stack<T>()

來源:
Stack.cs
來源:
Stack.cs
來源:
Stack.cs

初始化 Stack<T> 類別的新執行個體，這個執行個體為空白且具有預設的初始容量。

public:
 Stack();
public Stack ();
Public Sub New ()

範例

下列程式代碼範例示範此建構函式和泛型類別的 Stack<T> 數個方法。

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

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。

如果可以估計集合的大小，則指定初始容量就不需要在將元素加入 至 Stack<T>時執行一些重設大小作業。

您可以藉由呼叫 TrimExcess來減少容量。

此建構函式是 O (1) 作業。

適用於

Stack<T>(IEnumerable<T>)

來源:
Stack.cs
來源:
Stack.cs
來源:
Stack.cs

初始化 Stack<T> 類別的新執行個體，其包含從指定之集合複製的項目，且具有容納複製之項目數目的足夠容量。

public:
 Stack(System::Collections::Generic::IEnumerable<T> ^ collection);
public Stack (System.Collections.Generic.IEnumerable<T> collection);
new System.Collections.Generic.Stack<'T> : seq<'T> -> System.Collections.Generic.Stack<'T>
Public Sub New (collection As IEnumerable(Of T))

參數

collection
IEnumerable<T>

要複製項目的來源集合。

例外狀況

ArgumentNullException

collection 為 null。

範例

下列程式代碼範例示範此建構函式和泛型類別的 Stack<T> 數個方法。

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

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。

如果可以估計集合的大小，則指定初始容量就不需要在將元素加入 至 Stack<T>時執行一些重設大小作業。

您可以藉由呼叫 TrimExcess來減少容量。

元素會以集合的 讀取IEnumerator<T>順序複製到 Stack<T> 。

此建構函式是 O (n) 作業，其中 n 是中的 collection項目數目。

另請參閱

適用於

Stack<T>(Int32)

來源:
Stack.cs
來源:
Stack.cs
來源:
Stack.cs

初始化 Stack<T> 類別的新執行個體，其為空白且具有指定的初始容量或預設的初始容量 (兩者中較大的那一個)。

public:
 Stack(int capacity);
public Stack (int capacity);
new System.Collections.Generic.Stack<'T> : int -> System.Collections.Generic.Stack<'T>
Public Sub New (capacity As Integer)

參數

capacity
Int32

Stack<T> 可包含的初始項目數。

例外狀況

ArgumentOutOfRangeException

capacity 小於零。

備註

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。

如果可以估計集合的大小，則指定初始容量就不需要在將元素加入 至 Stack<T>時執行一些重設大小作業。

您可以藉由呼叫 TrimExcess來減少容量。

此建構函式是 O (n) 工作，其中 n 是 capacity。

適用於