Stack.Clone() Method in C#

This method is used to create a shallow copy of the Stack. It just creates a copy of the Stack. The copy will have a reference to a clone of the internal data array but not a reference to the original internal data array.

Syntax: public virtual object Clone ();

Return Value: The method returns an Object which is just the shallow copy of the Stack.

Example 1: Let’s see an example without using a Clone() method and directly copying a Stack using assignment operator ‘=’. In the below code, we can see even if we Pop() elements from myStack2, contents of myStack is also changed. This is because ‘=’ just assigns the reference of myStack to myStack2 and does not create any new Stack. But Clone() creates a new Stack.

// C# program to Copy a Stack using
// the assignment operator
using System;
using System.Collections;

class GFG {

    // Main Method
    public static void Main(string[] args)
    {

        Stack myStack = new Stack();
        myStack.Push("C");
        myStack.Push("C++");
        myStack.Push("Java");
        myStack.Push("C#");

        // Creating a copy using the
        // assignment operator.
        Stack myStack2 = myStack;

        // Removing top most element
        myStack2.Pop();
        PrintValues(myStack);
    }

    public static void PrintValues(IEnumerable myCollection)
    {
        // This method prints all
        // the elements in the Stack.
        foreach(Object obj in myCollection)
            Console.WriteLine(obj);
    }
}

Output:

Java
C++
C

Example 2:

// C# program to illustrate the use
// of Stack.Clone() Method
using System;
using System.Collections;

class MainClass {

    // Main Method
    public static void Main(string[] args)
    {

        Stack myStack = new Stack();
        myStack.Push("1st Element");
        myStack.Push("2nd Element");
        myStack.Push("3rd Element");
        myStack.Push("4th Element");

        // Creating copy using Clone() method
        Stack myStack3 = (Stack)myStack.Clone();

        // Removing top most element
        myStack3.Pop();
        PrintValues(myStack);
    }

    public static void PrintValues(IEnumerable myCollection)
    {
        // This method prints all the
        // elements in the Stack.
        foreach(Object obj in myCollection)
            Console.WriteLine(obj);
    }
}

Output:

4th Element
3rd Element
2nd Element
1st Element

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.stack.clone?view=netframework-4.7.2#System_Collections_Stack_Clone