using System;

​

public class UserInput

{

    public static double Get(string name, double min, double max)

    {

        double result = 0;

        bool validInput = false;

        while (!validInput)

        {

            Console.Write("Enter Now: ");

            string inputStr = Console.ReadLine();

            if (double.TryParse(inputStr, out result))

            {

                if (result >= min && result <= max)

                {

                    validInput = true;

                }

            }

​

            if (!validInput)

            {

                Console.WriteLine("Invalid input. Please enter a valid input within the accepted range.");

            }

        }

​

        return result;

    }

​

    public static int Get(string name, int min, int max)

    {

        return (int)Get(name, (double)min, (double)max);

    }

}

​

public class Mortgage

{

    // Properties/fields for Loan, Rate & Term

    public double Loan { get; set; }

​

    public double Rate { get; set; }

​

    public int Term { get; set; }

​

    // Payment, TotalCost & TotalInterest readonly properties

    private double _payment;

    public double Payment

    {

        get

        {

            if (_payment == 0)

            {

                _payment = CalcPayment(Loan, Rate, Term);

            }

​

            return _payment;

        }

    }

​

    private double _totalCost;

    public double TotalCost

    {

        get

        {

            if (_totalCost == 0)

            {

                _totalCost = CalcTotalCost(Payment, Term);

            }

​

            return _totalCost;

        }

    }

​

    private double _totalInterest;

    public double TotalInterest

    {

        get

        {

            if (_totalInterest == 0)

            {

                _totalInterest = CalcTotalInterest(TotalCost, Loan);

            }

​

            return _totalInterest;

        }

    }

​

    // Constructor to set Loan, Rate & Term

    public Mortgage()

    {

        Loan = UserInput.Get("Loan amount", 1, 100000000);

        Rate = UserInput.Get("Interest rate", 0, 25);

        Term = (int)UserInput.Get("Loan term in years", 1, 50);

    }

​

    // Method to calculate monthly payment

    private double CalcPayment(double principal, double annualRate, int months)

    {

        double monthlyRate = annualRate / 1200;

        double numerator = principal * monthlyRate;

        double denominator = 1 - Math.Pow(1 + monthlyRate, -months);

        return numerator / denominator;

    }

​

    // Method to calculate total cost

    private double CalcTotalCost(double payment, int months)

    {

        return payment * months;

    }

​

    // Method to calculate total interest

    private double CalcTotalInterest(double cost, double principal)

    {

        return cost - principal;

    }

​

    public override string ToString()

    {

        if (Loan == 0 || Term == 0 || Rate == 0)

        {

            return "Empty Mortgage";

        }

        else

        {

            return "Mortgage of ${Loan:F2} at {Rate:F2}% for {Term} months";

        }

    }

}

​

public class MainClass

{

    public static void Main()

    {

        int numMortgages = 0;

        Console.WriteLine("Hello, welcome to the mortgage calculator");

        Console.WriteLine("-----------------------------------");

        // Prompt the user to enter the number of mortgages

        while (numMortgages <= 0 || numMortgages > 10)

        {

            Console.Write("Please enter the number of mortgages (max 10): ");

            string inputStr = Console.ReadLine();

            int.TryParse(inputStr, out numMortgages);

        }

        Console.WriteLine(" ");

        Console.WriteLine("Please enter your Loan amount, your rate, and your term, one after the other.");

​

        Mortgage[] mortgages = new Mortgage[numMortgages];

        // Loop through each mortgage and get user input

        for (int i = 0; i < numMortgages; i++)

        {

            Console.WriteLine("\nMortgage");

            mortgages[i] = new Mortgage();

            // Output the mortgage details in tabular form

            Console.WriteLine("{0,-10} {1,-10} {2,-10} {3,-10} {4,-10} {5,-10}", "Loan", "Rate", "Months", "Payment", "TotalCost", "Interest");

            Console.WriteLine("{0,-10:F2} {1,-10:F2}% {2,-10} {3,-10:F2} {4,-10:F2} {5,-10:F2}", mortgages[i].Loan, mortgages[i].Rate, mortgages[i].Term * 12, mortgages[i].Payment, mortgages[i].TotalCost, mortgages[i].TotalInterest);

        }

    }

}