using System;

public class Program

{

    public static void Main()

    {

        private void btnClear_Click(object sender, RoutedEventArgs e)

        {

            //Clear all input & output

            tbxUnpaidBalance.Text = "";

            tbxStudentType.Text = "";

            tbxNewBalance.Text = "";

            tbxMonthlyInterestRate.Text = "";

            tbxMinimumPaymentDue.Text = "";

            tbxInterestAmt.Text = "";

        }

​

        private void btnCalculate_Click(object sender, RoutedEventArgs e)

        {

            // Define Unpaid Balance

            double dUnpaidBalance;

​

            //Check to validate the number

            if (!double.TryParse(tbxUnpaidBalance.Text, out dUnpaidBalance))

            {

                MessageBox.Show("Please enter a vaild number");

                return;

            }

​

            //Check to make sure the number is positive

            if(dUnpaidBalance <0)

            {

                MessageBox.Show("Please enter a positive number");

                return;

            }

​

            //Read Student Type

            string strStudentType = tbxStudentType.Text;

​

            //Make Case Insensitive

            strStudentType = strStudentType.ToUpper();

​

            //Test for G or U

            if (!(strStudentType == "G" || strStudentType == "U"))

            {

                MessageBox.Show("Please enter a U for Undergrad or a G for Graduate");

                return;

            }

​

            //Define Monthly Interest Rate

            double dMonthlyInterestRate = 1.25;

            //Calculate Monthly Interest Rate using Unpaid Balance

            if (dUnpaidBalance > 500 && dUnpaidBalance <= 1000)

            {

                dMonthlyInterestRate = 1.25;

            }

            else if (dUnpaidBalance >= 0 && dUnpaidBalance <= 500)

            {

                dMonthlyInterestRate = 1.00;

            }

            else

            {

                dMonthlyInterestRate = 1.50;

            }

​

            //Show Interest Rate in Tbx

            tbxMonthlyInterestRate.Text = Convert.ToString(dMonthlyInterestRate);

​

            //Define & Calculate Interest Amount

            double dInterestAmount = Math.Round((dMonthlyInterestRate * dUnpaidBalance),2);

​

            //Show Interest Amount in Tbx

            tbxInterestAmt.Text = Convert.ToString(dInterestAmount);

​

            //Define & Calculate New Balance

            double dNewBalance = Math.Round((dInterestAmount + dUnpaidBalance),2);

​

            //Show New Blance in Tbx

            tbxNewBalance.Text = Convert.ToString(dNewBalance);

​

            //Define Minimum Payment

            double dMinimumPayment;

​

            //Minimum Payment G Conditions

            if (strStudentType == "G" && dNewBalance < 50)

            {

                dMinimumPayment = dNewBalance;

            }

            else if (strStudentType == "G" && dNewBalance > 50 && dNewBalance <500)

            {

                dMinimumPayment = 25;

            }

            else if (strStudentType == "G" && dNewBalance > 500 & dNewBalance <1000)

            {

                dMinimumPayment = 75;

            }

            else

            {

                dMinimumPayment = Math.Round((dNewBalance * .10),2);

            }

​

            //Minimum Payment U Conditions

            if (strStudentType == "U" && dNewBalance < 50)

            {

                dMinimumPayment = dNewBalance;

            }

            else if (strStudentType == "U" && dNewBalance > 50 && dNewBalance < 500)

            {

                dMinimumPayment = 35;

            }

            else if (strStudentType == "U" && dNewBalance > 500 & dNewBalance < 1000)

            {

                dMinimumPayment = 100;

            }

            else

            {

                dMinimumPayment = Math.Round((dNewBalance * .13),2);

            }

​

            //Show Minimum Payment in Tbx

            tbxMinimumPaymentDue.Text = Convert.ToString(dMinimumPayment);

        }

    }

}

​

    }

}