Stack<T>.Count Stack<T>.Count Stack<T>.Count Stack<T>.Count Property

定義

Stack<T> に格納されている要素の数を取得します。Gets the number of elements contained in the Stack<T>.

public:
 property int Count { int get(); };
public int Count { get; }
member this.Count : int
Public ReadOnly Property Count As Integer

プロパティ値

Stack<T> に格納されている要素の数。The number of elements contained in the Stack<T>.

実装

次のコード例は、 Stack<T> Countプロパティを含む、ジェネリッククラスのいくつかのプロパティとメソッドを示しています。The following code example demonstrates several properties and methods of the Stack<T> generic class, including the Count property.

このコード例では、既定の容量を持つ文字列のスタックPushを作成し、メソッドを使用して5つの文字列をスタックにプッシュします。The code example creates a stack of strings with default capacity and uses the Push method to push five strings onto the stack. スタックの要素が列挙され、スタックの状態が変更されることはありません。The elements of the stack are enumerated, which does not change the state of the stack. Popメソッドは、スタックから最初の文字列をポップするために使用されます。The Pop method is used to pop the first string off the stack. メソッドは、スタック上の次の項目を確認するために使用されPop 、その後、メソッドを使用してポップします。 PeekThe Peek method is used to look at the next item on the stack, and then the Pop method is used to pop it off.

メソッドToArrayは、配列を作成してスタック要素をコピーするために使用されます。次に、 Stack<T>によってIEnumerable<T>取得されるコンストラクターに配列が渡されます。その後、要素の順序を逆にしてスタックのコピーが作成されます。The ToArray method is used to create an array and copy the stack elements to it, then the array is passed to the Stack<T> constructor that takes IEnumerable<T>, creating a copy of the stack with the order of the elements reversed. コピーの要素が表示されます。The elements of the copy are displayed.

スタックのサイズの2倍の配列が作成CopyToされ、メソッドを使用して配列の途中から配列の要素がコピーされます。An array twice the size of the stack is created, and the CopyTo method is used to copy the array elements beginning at the middle of the array. Stack<T>コンストラクターは、要素の順序を逆にしてスタックのコピーを作成するために再び使用されます。したがって、3つの null 要素が末尾にあります。The Stack<T> constructor is used again to create a copy of the stack with the order of elements reversed; thus, the three null elements are at the end.

メソッドは、文字列 "4" がスタックの最初のコピーに含まれていることを示すために使用Clearされます。その後Count 、メソッドはコピーをクリアし、プロパティはスタックが空であることを示します。 ContainsThe Contains method is used to show that the string "four" is in the first copy of the stack, after which the Clear method clears the copy and the Count property shows that the stack is empty.

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
 */
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

注釈

の容量Stack<T>は、 Stack<T>が格納できる要素の数です。The capacity of the Stack<T> is the number of elements that the Stack<T> can store. Countは、 Stack<T>実際に内にある要素の数です。Count is the number of elements that are actually in the Stack<T>.

容量は常に Count 以上です。The capacity is always greater than or equal to Count. 要素を追加するときに Count が容量を上回る場合、容量は、古い要素をコピーして新しい要素を追加する前に、内部配列を自動的に再割り当てすることによって増加します。If Count exceeds the capacity while adding elements, the capacity is increased by automatically reallocating the internal array before copying the old elements and adding the new elements.

このプロパティ値を取得することは、O(1) 操作になります。Retrieving the value of this property is an O(1) operation.

適用対象