P1: Arithmetic Calculator

Program 1: Basic Arithmetic Calculator

This program introduces variables, basic data types, input/output, and simple conditionals. It performs arithmetic operations based on user input.

using System;

class BasicCalculator
{
    static void Main()
    {
        Console.Write("Enter the first number: ");
        int num1 = Convert.ToInt32(Console.ReadLine());

        Console.Write("Enter the second number: ");
        int num2 = Convert.ToInt32(Console.ReadLine());

        Console.Write("Enter operation (+, -, *, /): ");
        char operation = Console.ReadKey().KeyChar;
        Console.WriteLine();

        int result;
        switch (operation)
        {
            case '+':
                result = num1 + num2;
                break;
            case '-':
                result = num1 - num2;
                break;
            case '*':
                result = num1 * num2;
                break;
            case '/':
                result = num1 / num2;
                break;
            default:
                Console.WriteLine("Invalid operation.");
                return;
        }

        Console.WriteLine($"Result: {num1} {operation} {num2} = {result}");
    }
}

Using modern and simplified features of C#

Console.Write("Enter the first number: ");
var num1 = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter the second number: ");
var num2 = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter operation (+, -, *, /): ");
var operation = Console.ReadKey().KeyChar;
Console.WriteLine();

var result = operation switch
{
    '+' => num1 + num2,
    '-' => num1 - num2,
    '*' => num1 * num2,
    '/' => num1 / num2,
    _ => throw new InvalidOperationException("Invalid operation.")
};

Console.WriteLine($"Result: {num1} {operation} {num2} = {result}");