C#: Remove duplicates from a given stack

C# Sharp Stack: Exercise-12 with Solution

Write a C# program to remove duplicates from a given stack.

Sample Solution:

C# Code:

using System;
using System.Collections.Generic;
public class Stack
{
    private int[] items;
    private int top;

    public Stack(int size)
    {
        items = new int[size];
        top = -1;
    }

    public bool IsEmpty()
    {
        return top == -1;
    }

    public bool IsFull()
    {
        return top == items.Length - 1;
    }

    public void Push(int item)
    {
        if (IsFull())
        {
            Console.WriteLine("Stack Full!");
            return;
        }

        items[++top] = item;
    }

    public int Pop()
    {
        if (IsEmpty())
        {
            Console.WriteLine("Stack underflow");
            return -1;
        }

        return items[top--];
    }

    public int Peek()
    {
        if (IsEmpty())
        {
            Console.WriteLine("Stack is empty");
            return -1;
        }

        return items[top];
    }

    public static int Size(Stack stack)
    {
        return stack.top + 1;
    }

    // Method to remove duplicates from a given stack 
    public static void Remove_Duplicates(Stack stack)
    {
        if (stack == null || stack.IsEmpty())
            return;

        HashSet set = new HashSet();

        Stack tempStack = new Stack(Size(stack));

        while (!stack.IsEmpty())
        {
            int current = stack.Pop();
            if (!set.Contains(current))
            {
                set.Add(current);
                tempStack.Push(current);
            }
        }

        while (!tempStack.IsEmpty())
        {
            stack.Push(tempStack.Pop());
        }
    }


    public static void Display(Stack stack)
    {
        if (stack.IsEmpty())
        {
            Console.WriteLine("Stack is empty");
            return;
        }

        Console.WriteLine("Stack elements:");
        for (int i = stack.top; i >= 0; i--)
        {
            Console.Write(stack.items[i]+" ");
        }
    }

}

public class Program
{
    public static void Main(string[] args)
    {
        Console.WriteLine("Initialize a stack:");
        Stack stack = new Stack(10);
        Console.WriteLine("Input some elements onto the stack:");
        stack.Push(10);
        stack.Push(50);
        stack.Push(30);
        stack.Push(40);
        stack.Push(50);
        stack.Push(50);
        stack.Push(10);
        Stack.Display(stack);
        Console.WriteLine("\nRemove duplicates from the said stack:");
        Stack.Remove_Duplicates(stack);
        Stack.Display(stack);
    }
}

Sample Output:

Initialize a stack:
Input some elements onto the stack:
Stack elements:
10 50 50 40 30 50 10 
Remove duplicates from the said stack:
Stack elements:
10 50 40 30 

Flowchart:

C# Sharp Code Editor:

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