using System;
using System.Collections.Generic;
using System.Collections;
 
class ProgrammingLanguagesStack
{
    static void Main(string[] args)
    {
        // Create a stack representing the order of programming languages learned
        Stack<string> languageStack = new Stack<string>();
 
        Console.WriteLine("Programming Languages Learning History (LIFO Stack):");
        Console.WriteLine("===================================================");
 
        // Push languages onto the stack in the order they were learned
        languageStack.Push("BASIC");
        languageStack.Push("Pascal");
        languageStack.Push("C");
        languageStack.Push("C++");
        languageStack.Push("Java");
        languageStack.Push("Python");
        languageStack.Push("JavaScript");
 
        Console.WriteLine("\nLanguages learned (most recent first):");
        foreach (string language in languageStack)
        {
            Console.WriteLine(language);
        }
 
        Console.WriteLine("\nTotal languages learned: " + languageStack.Count);
 
        // Check if stack contains specific languages
        Console.WriteLine("\nStack contains Java: " + languageStack.Contains("Java"));
        Console.WriteLine("Stack contains Ruby: " + languageStack.Contains("Ruby"));
 
        Console.WriteLine("\nRemoving languages from stack (LIFO order):");
 
        // Pop languages from the stack
        while (languageStack.Count > 0)
        {
            string language = languageStack.Pop();
            Console.WriteLine("Removed: " + language + " (Remaining in stack: " + languageStack.Count + ")");
        }
 
        Console.WriteLine("\nStack is now empty. Count: " + languageStack.Count);
 
        // Demonstrate stack again with a different scenario
        Console.WriteLine("\n--- New Scenario: Current Project Languages Stack ---");
 
        Stack<string> projectStack = new Stack<string>();
        projectStack.Push("SQL");
        projectStack.Push("C#");
        projectStack.Push("JavaScript");
        projectStack.Push("HTML/CSS");
 
        Console.WriteLine("\nCurrent project technology stack (top to bottom):");
        foreach (string tech in projectStack)
        {
            Console.WriteLine(tech);
        }
    }
}

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