C＃|从堆栈中删除所有对象

堆栈表示对象的后进先出集合。当您需要对项目进行后进先出的访问时使用。在列表中添加项目时，称为推送项目，而在删除项目时，则称为弹出项目。 Stack .Clear方法用于从Stack 中删除所有对象。此方法是O(n)运算，其中n是Count。

特性：

• 堆栈的容量是堆栈可以容纳的元素数量。将元素添加到堆栈后，容量会根据需要通过重新分配自动增加。
• 如果Count小于堆栈的容量，则Push是O(1)运算。如果需要增加容量以容纳新元素，则Push变为O(n)操作，其中n为Count。 Pop是O(1)运算。
• 堆栈接受null作为有效值，并允许重复的元素。

句法：

public virtual void Clear();

下面给出了一些示例，以更好地理解实现。

范例1：

// C# code to Remove all
// objects from the Stack
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a Stack of strings
        Stack myStack = new Stack();
  
        // Inserting the elements into the Stack
        myStack.Push("1st Element");
        myStack.Push("2nd Element");
        myStack.Push("3rd Element");
        myStack.Push("4th Element");
        myStack.Push("5th Element");
        myStack.Push("6th Element");
  
        // Displaying the count of elements
        // contained in the Stack before
        // removing all the elements
        Console.Write("Total number of elements in the Stack are : ");
  
        Console.WriteLine(myStack.Count);
  
        // Removing all elements from Stack
        myStack.Clear();
  
        // Displaying the count of elements
        // contained in the Stack after
        // removing all the elements
        Console.Write("Total number of elements in the Stack are : ");
  
        Console.WriteLine(myStack.Count);
    }
}

输出：

Total number of elements in the Stack are : 6
Total number of elements in the Stack are : 0

范例2：

// C# code to Remove all
// objects from the Stack
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a Stack of Integers
        Stack myStack = new Stack();
  
        // Inserting the elements into the Stack
        myStack.Push(3);
        myStack.Push(5);
        myStack.Push(7);
        myStack.Push(9);
        myStack.Push(11);
  
        // Displaying the count of elements
        // contained in the Stack before
        // removing all the elements
        Console.Write("Total number of elements in the Stack are : ");
  
        Console.WriteLine(myStack.Count);
  
        // Removing all elements from Stack
        myStack.Clear();
  
        // Displaying the count of elements
        // contained in the Stack after
        // removing all the elements
        Console.Write("Total number of elements in the Stack are : ");
  
        Console.WriteLine(myStack.Count);
    }
}

输出：

Total number of elements in the Stack are : 5
Total number of elements in the Stack are : 0

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.stack.clear?view=netframework-4.7.2