C.net example

// Declare variables and then initialize to zero.
    int num1 = 0; int num2 = 0;

// Display title as the C# console calculator app.
    Console.WriteLine("Console Calculator in C#\r");
    Console.WriteLine("------------------------\n");

// Ask the user to type the first number.
    Console.WriteLine("Type a number, and then press Enter");
    num1 = Convert.ToInt32(Console.ReadLine());

// Ask the user to type the second number.
    Console.WriteLine("Type another number, and then press Enter");
    num2 = Convert.ToInt32(Console.ReadLine());

// Ask the user to choose an option.
    Console.WriteLine("Choose an option from the following list:");
    Console.WriteLine("\ta - Add");
    Console.WriteLine("\ts - Subtract");
    Console.WriteLine("\tm - Multiply");
    Console.WriteLine("\td - Divide");
    Console.Write("Your option? ");

// Use a switch statement to do the math.
    switch (Console.ReadLine())
    {
        case "a":
            Console.WriteLine($"Your result: {num1} + {num2} = " + (num1 + num2));
            break;
        case "s":
            Console.WriteLine($"Your result: {num1} - {num2} = " + (num1 - num2));
            break;
        case "m":
            Console.WriteLine($"Your result: {num1} * {num2} = " + (num1 * num2));
            break;
        case "d":
            Console.WriteLine($"Your result: {num1} / {num2} = " + (num1 / num2));
            break;
    }
    // Wait for the user to respond before closing.
    Console.Write("Press any key to close the Calculator console app...");
    Console.ReadKey();

Arrays:

Make a quiz:

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

class Quiz
{
    static void Main()
    {
        List<Question> questions = new List<Question>
        {
            new Question("What is the capital of France?", new List<string>{"A. Paris", "B. London", "C. Berlin", "D. Madrid"}, "A"),
            new Question("Which planet is known as the Red Planet?", new List<string>{"A. Earth", "B. Mars", "C. Jupiter", "D. Venus"}, "B"),
            new Question("What is the largest mammal on Earth?", new List<string>{"A. Elephant", "B. Blue Whale", "C. Giraffe", "D. Lion"}, "B"),
            new Question("Who wrote 'Romeo and Juliet'?", new List<string>{"A. Charles Dickens", "B. William Shakespeare", "C. Jane Austen", "D. Mark Twain"}, "B"),
            new Question("What is the capital of Japan?", new List<string>{"A. Beijing", "B. Seoul", "C. Tokyo", "D. Bangkok"}, "C"),
        };

Console.WriteLine("Welcome to the Quiz!");
        Console.WriteLine("Answer the following questions:");

int score = 0;

foreach (var question in questions)
        {
            Console.WriteLine(question.QuestionText);
            foreach (var option in question.Options)
            {
                Console.WriteLine(option);
            }

Console.Write("Your answer: ");
            string userAnswer = Console.ReadLine().ToUpper();

if (userAnswer == question.CorrectAnswer)
            {
                Console.WriteLine("Correct!\n");
                score++;
            }
            else
            {
                Console.WriteLine($"Incorrect. The correct answer is {question.CorrectAnswer}.\n");
            }
        }

Console.WriteLine($"Quiz completed! Your score: {score}/{questions.Count}");
    }
}

class Question
{
    public string QuestionText { get; }
    public List<string> Options { get; }
    public string CorrectAnswer { get; }

public Question(string questionText, List<string> options, string correctAnswer)
    {
        QuestionText = questionText;
        Options = options;
        CorrectAnswer = correctAnswer;
    }
}