csharp beginner

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace csharp
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hallo Welt");

            int x;

            Console.WriteLine("#######MENU########");
            Console.WriteLine("1-while loop");
            Console.WriteLine("2-if else statement");
            Console.WriteLine("3-switch statement");
            Console.WriteLine("please choose one of them.....");
            x=int.Parse(Console.ReadLine());

            switch (x)
            {
                case 1:
                    Console.WriteLine("result= result + (your num)/2"); 
                    Console.Write("enter a nummer biger than 10 : ");
                    int add = int.Parse(Console.ReadLine());
                    int result = 0;
                    while (add / 2>0)
                    {
                        result = result + add;
                        add /= 2;
                    }
                    Console.WriteLine("the result is: {0}", result);
                    break;

                case 2:
                    Console.WriteLine("this program gives you information about your pulse");
                    Console.WriteLine("enter your pulse");
                    int pulse = int.Parse(Console.ReadLine());
                    if (pulse >= 60 && pulse <= 100)
                    {
                        Console.WriteLine("it is only normal for mature");
                    }
                    else if (pulse > 100 && pulse <= 120)
                    {
                        Console.WriteLine("it is only normal for kid");
                    }
                    else if (pulse > 120 && pulse <= 140)
                    {
                        Console.WriteLine("it is only normal for baby");
                    }
                    else
                    {
                        Console.WriteLine("it is not normal!");
                    }
                    break;

                case 3:
                    Console.WriteLine("this program gives you information about languages");
                    Console.WriteLine("greetings of nationalites");
                    Console.WriteLine("#######GREETINGS########");
                    Console.WriteLine("1-Hallo!");
                    Console.WriteLine("2-Hi!");
                    Console.WriteLine("3-Merhaba!");
                    Console.WriteLine("4-Ciao!");
                    Console.WriteLine("5-Salut!");
                    Console.WriteLine("choose one of them: ");
                    int choose = int.Parse(Console.ReadLine());
                    switch (choose)
                    {
                        case 1:
                            Console.WriteLine("it is GERMAN");
                            break;
                        case 2:
                            Console.WriteLine("it is ENGLISH");
                            break;
                    case 3:
                            Console.WriteLine("it is TURKISH");
                            break;
                        case 4:
                            Console.WriteLine("it is ITALIAN");
                            break;
                        case 5:
                            Console.WriteLine("it is FRENCH");
                            break;
                        default:
                            Console.WriteLine("typing error");
                            break;
                    }
                    break;

                default:
                    Console.WriteLine("choosing error");
                    break;
            }


        }
    }
}