Question

a.      You must use proper error and exception handling (try, catch) in the application. [5 marks]

b.      Accept the users first and last name store in two SEPARATE variables. [2 marks]

c.      Accept two numbers:

                                i.     validate that the user has entered numbers for each input. [3 marks]

                               ii.     For invalid numbers ask the user to re-enter the number [2 marks] 

                              iii.     If the user enters a number greater than 500 throw an exception, display a message that numbers should be less than 1000. [3 marks]

d.      Give the user the option to do any one of the following calculations (i.e prompt for user input):

·        add both numbers

·        multiply both numbers

·        divide the second number by the first.

·        subtract the first number from the second.

You must use an if-Else-Elseif to evaluate the user selection. [3 marks]

 

e.      After the calculation is done if the result is greater than 50 multiply the result by two and subtract 4.  If the result is less than 50 but greater than 10 multiply the result by 7 and add 2. If the result is less than 10 do nothing.  You must use a switch statement to get full marks. [5 marks]

f.       Display the users first and last name along with the calculation result on the screen in this format> “Hello <first name> <last name> your answer is <answer>  [2 marks]

The user should have the option to repeat the process of entering two numbers until they enter the word “END” to exit the application.

Answer 1

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ErrorHandling

{

  class Program

  {

    static void Main(string[] args)

    {

      //Two seperate string variables to store user's first and last names

      string firstName, lastName;

      //Two seperate integer variable to store two numbers

      double num1 = 0, num2 = 0;

      bool validNum1 = false,validNum2 = false;

      Console.WriteLine("=====================================");

      Console.WriteLine("\tPROGRAM EXECUTION");

      Console.WriteLine("=====================================");

      //Read user's first name and last name

      Console.Write("Enter your first name : ");

      firstName = Console.ReadLine();

      Console.Write("Enter your last name : ");

      lastName = Console.ReadLine();

      Console.WriteLine();

      //Accept two numbers

      //Validate that the user has entered numbers for each input.

      string choice = "";

      //Loop until the user want's to exit

      while (!choice.Equals("END", StringComparison.InvariantCultureIgnoreCase))

      {

        //Re-prompt the user to enter number1 if invalid number is entered

        while (validNum1 == false)

        {

          //Using try catch statements

          try

          {

            //Read first number

            Console.Write("Enter first number : ");

            string n1 = Console.ReadLine();

            //If the entered input is a number

            if (double.TryParse(n1, out num1))

            //If it is greater than 500 throws exception

            if (num1 > 500) { throw new Exception(); }

            //else set flag to true

            else { validNum1 = true; }

            else

            //If input is not a number throws formatted exception

            throw new FormatException();

          }

          catch (FormatException) { Console.WriteLine("Please enter number's only...Try again"); }

          catch (Exception) { Console.WriteLine("Numbers should be less than 1000."); }

        }

        while (validNum2 == false)

        {

          try

          {

            //Read second number

            Console.Write("Enter second number : ");

            string n2 = Console.ReadLine();

            //If the entered input is a number

            if (double.TryParse(n2, out num2))

            //If it is greater than 500 throws exception

            if (num2 > 500){ throw new Exception(); }

            //else set flag to true

            else { validNum2 = true; }

            else

            //If input is not a number throws formatted exception

            throw new FormatException();

          }

          catch (FormatException) { Console.WriteLine("Please enter number's only...Try again"); }

          catch (Exception) { Console.WriteLine("Numbers should be less than 1000."); }

        }

        int option = 1;

        double answer = 0;

        //Display optiona to user

        Console.WriteLine("\n=====================================");

        Console.WriteLine("Select one of the following operations : ");

        Console.WriteLine("1. Add both numbers\n2. Multiply both numbers");

        Console.WriteLine("3. Divide the second number by the first\n4. Subtract the first number from the second.");

        //Read user option

        Console.Write("Enter your choice: ");

        option = int.Parse(Console.ReadLine());

        //Validate user option

        while (option != 1 && option != 2 && option != 3 && option != 4)

        {

          Console.WriteLine("Invalid Choice...Try again...");

          Console.Write("Enter your choice : ");

          option = int.Parse(Console.ReadLine());

        }

        //Perform operation based on the option

        if (option == 1) { answer = num1 + num2; }

        else if (option == 2) { answer = num1 * num2; }

        else if (option == 3) { answer = num2 / num1; }

        else if (option == 4) { answer = num2 - num1; }

        //Switch for further calculation

        int ch = (answer > 50) ? 1 : ((answer > 10 && answer < 50) ? 2 : 3);

        switch (ch)

        {

          case 1:

          answer = (answer * 2) - 4;

          break;

          case 2:

          answer = (answer * 7) + 2;

          break;

          case 3:

          break;

        }

        //Display output

        Console.WriteLine("Hello " + firstName + " " + lastName + " your answer is " + answer);

        validNum1 = false; validNum2 = false;

        Console.WriteLine("=====================================\n");

        //Prompt user whether the user wants to proceed or not

        Console.Write("Press END to exit...Any other key to continue...");

        choice = Console.ReadLine();

      }

    }

  }

}