C#: Merge two stacks into one

C# Sharp Stack: Exercise-17 with Solution

Write a C# program to merge two stacks into one.

Sample Solution:

C# Code:

using System;
using System.Collections;
using System.Collections.Generic;

public class Stack
{
    private int[] items; // Array to hold stack elements
    private int top; // Index indicating the top of the stack

    // Constructor to initialize the stack with a specified size
    public Stack(int size)
    {
        items = new int[size]; // Creating an array of integers with the given size
        top = -1; // Initializing top index to -1 indicating an empty stack
    }

    // Check if the stack is empty
    public bool IsEmpty()
    {
        return top == -1; // Stack is empty if top is -1
    }

    // Check if the stack is full
    public bool IsFull()
    {
        return top == items.Length - 1; // Stack is full if top equals the last index of the array
    }

    // Push an element onto the stack
    public void Push(int item)
    {
        if (IsFull()) // Check if the stack is full
        {
            Console.WriteLine("Stack Full!"); // Display a message indicating stack overflow
            return;
        }

        items[++top] = item; // Increment top and add the item to the stack
    }

    // Pop an element from the stack
    public int Pop()
    {
        if (IsEmpty()) // Check if the stack is empty
        {
            Console.WriteLine("Stack underflow"); // Display a message indicating stack underflow
            return -1;
        }

        return items[top--]; // Return and decrement top to remove the element from the stack
    }

    // Peek at the top element of the stack without removing it
    public int Peek()
    {
        if (IsEmpty()) // Check if the stack is empty
        {
            Console.WriteLine("Stack is empty"); // Display a message indicating the stack is empty
            return -1;
        }

        return items[top]; // Return the top element of the stack
    }

    // Static method to get the size of a stack
    public static int Size(Stack stack)
    {
        return stack.top + 1; // Return the size of the stack based on the current top index
    }

    // Static method to count all the elements in a stack
    public static int Count(Stack stack)
    {
        int count = 0; // Initialize count variable to track the number of elements

        Stack temp = new Stack(Size(stack)); // Create a temporary stack to preserve the original stack order

        // Move elements from the original stack to the temporary stack and count them
        while (!stack.IsEmpty())
        {
            temp.Push(stack.Pop()); // Move elements from original stack to temporary stack
            count++; // Increment count for each element moved
        }

        // Restore the original stack by moving elements back from the temporary stack
        while (!temp.IsEmpty())
        {
            stack.Push(temp.Pop()); // Move elements back to the original stack
        }

        return count; // Return the total count of elements in the stack
    }

    // Static method to clear the stack by popping all elements
    public static void Clear(Stack stack)
    {
        while (!stack.IsEmpty())
        {
            stack.Pop(); // Remove elements from the stack until it's empty
        }
    }

    // Method to merge two stacks
    public static Stack MergeStacks(Stack stack1, Stack stack2)
    {
        Stack result = new Stack(Size(stack1) + Size(stack2)); // Create a new stack to hold merged elements

        // Push elements from stack1 to the result stack
        while (!stack1.IsEmpty())
        {
            result.Push(stack1.Pop());
        }

        // Push elements from stack2 to the result stack
        while (!stack2.IsEmpty())
        {
            result.Push(stack2.Pop());
        }

        return result; // Return the merged stack
    }

    // Method to display the elements of the stack
    public static void Display(Stack stack)
    {
        if (stack.IsEmpty()) // Check if the stack is empty
        {
            Console.WriteLine("Stack is empty"); // Display a message indicating the stack is empty
            return;
        }

        Console.WriteLine("\nStack elements:"); // Display a message indicating stack elements will be shown
        for (int i = stack.top; i >= 0; i--) // Loop through the stack elements
        {
            Console.Write(stack.items[i] + " "); // Print each element of the stack
        }
    }

}

public class Program
{
    public static void Main(string[] args)
    {
        Console.WriteLine("Initialize a stack:");
        Stack stack = new Stack(10); // Create a stack with a capacity of 10 elements

        Console.WriteLine("Input some elements onto the stack:");
        Stack stack1 = new Stack(3); // Create stack1 with a capacity of 3 elements
        stack1.Push(1); // Add elements to stack1
        stack1.Push(2);
        stack1.Push(3);
        Stack.Display(stack1); // Display elements of stack1

        Stack stack2 = new Stack(3); // Create stack2 with a capacity of 3 elements
        stack2.Push(4); // Add elements to stack2
        stack2.Push(5);
        stack2.Push(6);
        Stack.Display(stack2); // Display elements of stack2

        Console.WriteLine("\n\nMerged stacks:");
        Stack mergedStack = Stack.MergeStacks(stack1, stack2); // Merge stack1 and stack2 into mergedStack
        Stack.Display(mergedStack); // Display elements of mergedStack
    }
}

Sample Output:

Initialize a stack:
Input some elements onto the stack:

Stack elements:
3 2 1
Stack elements:
6 5 4

Merged stacks:

Stack elements:
4 5 6 1 2 3

Flowchart:

C# Sharp Code Editor:

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