using System;

​

//Create a Mortgage class

public class Mortage

{

    /*

    //Create three properties

    Principal should not be negative.

    Interest rate should be between 0.01 and 0.99. If violated, set 0.03 as the default value.

    Terms should be between 1 and 360. If violated, set 180 as the default value.

    */

    private double _Principal;

    public double Principal{

      get

      {

        return _Principal;

      }

      set

      {

        if (value >= 0)

        {

          _Principal = value;

        }

        else

        {

          _Principal = 0;

        }

      }

    }

    private double _IRate;

    public double IRate

    {

        get

        {

            return _IRate;

        }

        set

        {

            if (value >= 0.01 && value <= 0.99)

            {

                _IRate = value;

            }

            else

            {

                _IRate = 0.03;

            }

        }

    }

    private int _Terms;

    public int Terms

    {

        get

        {

            return _Terms;

        }

        set

        {

            if (value >= 1 && value <= 360)

            {

                _Terms = value;

            }

            else

            {

                _Terms = 180;

            }

        }

    }

    /*

    //Create three auto impelmented properties

    //monthly payment, total cost, total interest

    */

    public double MonthlyPayment {get;set;}

    public double TotalCost {get;set;}

    public double TotalInterest {get;set;}

    //default constructor

    public Mortage()

    {

    }

    //the second constructor with three parameters

    public Mortage(double p, double i, int t){

        Principal = p;

        IRate = i;

        Terms = t;

    }

    //Function: CalculatePayment

    double MonthlyIR;

    public void CalculatePayment()

    {

        MonthlyIR = IRate/12;

        MonthlyPayment = Principal * (MonthlyIR * Math.Pow((MonthlyIR + 1), Terms)) / ((Math.Pow((MonthlyIR + 1), Terms)-1));

        TotalCost = MonthlyPayment * Terms;

        TotalInterest = TotalCost - Principal;

    }

    //Function: CalculateClosingFees

    public double ClosingFees;

    public void CalculateClosingFees()

    {

        if (Terms == 180)

        {

            ClosingFees = 0.005 * Principal;

        }

        else if (Terms == 360)

        {

            ClosingFees = 0.004 * Principal;    

        }

        else

        {

            ClosingFees = 0.006 * Principal;

        }

    }

}

public class MainClass {

  public static void Main (string[] args) {

    //Print a message prompting the user to enter the principal.

    //Validation 1.1: Principal should be a double

    //Validation 1.2: Principal should not be negative.

      double Principal;

      string strPrincipal;

      bool success;

      Console.WriteLine("Please enter principal value.");

      strPrincipal = Console.ReadLine();

      success = double.TryParse(strPrincipal, out Principal);

      if (success)

      {

          if (Principal >= 0)

          {

          }

          else

          {

              Principal = 0;

          }

      }

      else

      {

          Console.WriteLine("Please enter a valid principal value.");

      }

    //Print a message prompting the user to enter the Interest Rate.

    //Validation 2.1: Interest rate should be a double

    //Validation 2.2: Interest rate should be between 0.01 and 0.99.

      double IRate;

      string strRate;

      bool success2;

      Console.WriteLine("Please enter the interest Rate.");

      strRate = Console.ReadLine();

      success2 = double.TryParse(strRate, out IRate);

      if (success2)

      {

          if (IRate >= 0.01 && IRate <= 0.99){}

          else {IRate = 0.03;}

      }

      else

      {

          Console.WriteLine("Please enter a valid interest Rate.");

      }

    //Print a message prompting the user to enter the terms (months)

    //Validation 3.1: Terms (months) should be an integer

    //Validation 3.2: Terms should be between 1 and 360.

      int Terms;

      string strTerms;

      bool success3;

      Console.WriteLine("Please enter the number of terms (months).");

      strTerms = Console.ReadLine();

      success3 = int.TryParse(strTerms, out Terms);

      if (success3)

      {

          if (Terms >= 1 && Terms <= 360){}

          else {Terms = 180;}

      }

      else

      {

          Console.WriteLine("Please enter a valid number of terms (months).");

      }

​

    //Create a mortgage object

    Mortage M1 = new Mortage (Principal, IRate, Terms);  

    //Use the mortgage object to call CalculatePayment() function and then print out monthly payment, total costs, and total interest

    //Use the mortgage object to call CalculateClosingFees() function and then print out closing fees.

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

      M1.CalculatePayment();

        Console.WriteLine("Monthly Payment: " + M1.MonthlyPayment.ToString("C2"));

        Console.WriteLine("Total Cost " + M1.TotalCost.ToString("C2"));

        Console.WriteLine("Total Interest: " + M1.TotalInterest.ToString("C2"));

      M1.CalculateClosingFees();  

        Console.WriteLine("Closing Fees: " + M1.ClosingFees.ToString("C2"));

  }

}