Практикум 1

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

namespace mainSolution
{
    class Program
    {
        public class MyException : Exception
        {
            public MyException(string messege) : base(message: messege + "\n\n\n Exception founded by Decibit\n\n\n") { }
            public MyException() : base()
            {

            }
            public void Messsage()
            {
                Console.WriteLine("\n\n\n\n\n\n Invalid number, please enter a number from 1 to 10 \n\n\n\n\n\n");
            }


        }



        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine("Enter the number (1 - 10) - number of problem");
                int ProblemNumber = Int32.Parse(Console.ReadLine());
                switch (ProblemNumber)
                {
                    case 1: { FirstSolve(); break; }
                    case 2: { SecondSolve(); break; }
                    case 3: { ThirdSolve(); break; }
                    case 4: { FourthSolve(); break; }
                    case 5: { FifthSolve(); break; }
                    case 6: { SixthSolve(); break; }
                    case 7: { SeventhSolve(); break; }
                    case 8: { EighthSlove(); break; }
                    case 9: { NinthSlove(); break; }
                    case 10: { TenthSlove(); break; }
                    default:
                        throw new MyException("");
                }

            }
            catch (MyException ex)
            {
                //Console.WriteLine(ex);
                Console.WriteLine(ex.Message);
                return;
                //throw;
            }

        }
        static void FirstSolve()
        {
            Console.WriteLine("Enter A:");
            int a = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            int b = int.Parse(Console.ReadLine());
            Console.WriteLine($"a + b = {0}", a + b);
        }
        static void SecondSolve()
        {
            Console.WriteLine("Enter A:");
            int a = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            int b = int.Parse(Console.ReadLine());
            Console.WriteLine($"{a} + {b} = {b} + {a}");
        }
        static void ThirdSolve()
        {
            Console.WriteLine("Enter A:");
            int a = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            int b = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            int c = int.Parse(Console.ReadLine());
            Console.WriteLine($"{a + b + c}");
        }
        static void FourthSolve()
        {
            Console.WriteLine("Enter A:");
            double a = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            double b = double.Parse(Console.ReadLine());
            Console.WriteLine($"{a} * {b} = {a * b : .#}");
        }
        static void FifthSolve()
        {
            Console.WriteLine("Enter A:");
            double a = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            double b = double.Parse(Console.ReadLine());
            try
            {

                if (b == 0) throw new DivideByZeroException();
                else    Console.WriteLine($"{a} / {b} = {a / b: .###}");

            }
            catch (DivideByZeroException error)
            {
                Console.WriteLine($"{error.Message} (founded by DeciBit)");
                //throw;
            }
        }
        static void SixthSolve()
        {
            Console.WriteLine("Enter A:");
            double a = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter B:");
            double b = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter C:");
            double c = double.Parse(Console.ReadLine());
            Console.WriteLine($"({a} + {b}) + {c} = {a} + ({b} + {c})");
        }



        static void SeventhSolve()
        {
            Console.WriteLine("Enter Denomination:");
            double a = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter Number of Bills:");
            double b = double.Parse(Console.ReadLine());
            Console.WriteLine($"Amount of Money : {a * b:#.##} р");
        }
        static void EighthSlove()
        {
            Console.WriteLine("Enter Deposit amount:");
            decimal a = decimal.Parse(Console.ReadLine());
            Console.WriteLine("Enter Interest on deposit:");
            decimal b = decimal.Parse(Console.ReadLine());
            Console.WriteLine($"Accrue in a year: {a * (b / 100) : .###}");
        }
        static void NinthSlove()
        {
            Console.WriteLine("Enter Deposit amount:");
            decimal a = decimal.Parse(Console.ReadLine());
            Console.WriteLine("Enter Interest on deposit:");
            decimal b = decimal.Parse(Console.ReadLine());
            Console.WriteLine($"Invoice amount in a year : {a + a * (b / 100) : .##}");
        }
        static void TenthSlove()
        {
            Console.WriteLine("What's your name?:");
            string s = Console.ReadLine();
            Console.WriteLine("How old are you?:");
            int old = int.Parse(Console.ReadLine());
            Console.WriteLine($"{s}, you were born in {2009 - old}");
        }

    }
}