Hospital Charges c#

What is the error?

I need help I tried your code but I couldnt get it to work. 

Thank you very much!!

It works now and the final code looks like this:


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Hospital_Charges
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        // These methods accept the number of days at the hospital
        // and medical charges as arguments and return the
        // equivalent total of charges.
        private double CalcStayCharges(double days)
        {
            return days * 350.0;
        }

        private double CalcMiscCharges(double medical, double surgical, double lab, double rehab)
        {
            return (medical + surgical + lab + rehab);
        }

        private double CalcTotalCharges(double days, double medical, double surgical, double lab, double rehab)
        {
            return CalcStayCharges(days) + CalcMiscCharges(medical, surgical, lab, rehab);
        }

        private void calculateButton_Click(object sender, EventArgs e)
        {
            // Variables to hold the number of days spent at the hospital, amount of medication, surgical, lab and rehab charges.
            double days, stayTotal, medical, surgical, lab, rehab, totalFees, totalCharges;

            // Get the number of days.
            if (!double.TryParse(daysTextBox.Text, out days) || days <= 0.0)
            {
                MessageBox.Show("Length of stay (days) is invalid. Please enter a valid number");
                daysTextBox.Focus();
                return;
               
            }

            // Get the medication charges

            if (!double.TryParse(medicationTextBox.Text, out medical) || medical < 0.0)
            {
                MessageBox.Show("Medication charges are invalid. Please enter a valid number");
                medicationTextBox.Focus();
                return;
            }

            // Get the surgical charges

            if (!double.TryParse(surgicalTextBox.Text, out surgical) || surgical < 0.0)
            {
                MessageBox.Show("Surgical charges are invalid. Please enter a valid number");
                surgicalTextBox.Focus();
                return;
            }

            // Get the lab fees

            if (!double.TryParse(labTextBox.Text, out lab) || lab < 0.0)
            {
                MessageBox.Show("Lab fees are invalid. Please enter a valid number");
                labTextBox.Focus();
                return;
            }

            // Get the physical rehabilitation charges

            if (!double.TryParse(rehabTextBox.Text, out rehab) || rehab < 0.0)
            {
                MessageBox.Show("Phycial rehabilitation charges are invalid. Please enter a valid number");
                rehabTextBox.Focus();
                return;
            }

            stayTotal = CalcStayCharges(days);
            totalStayLabel.Text = stayTotal.ToString("n2");

            // Calculate the total charges.
            totalCharges = CalcTotalCharges(days, medical, surgical, lab, rehab);
            // Display the total charges.
            totalLabel.Text = totalCharges.ToString("n2");


            // Calculate the other fees.
            totalFees = CalcMiscCharges(medical, surgical, lab, rehab);
            // Display the total Fees.
            miscLabel.Text = totalFees.ToString("n2");


            // Display the amount for medical
            listBox1.Items.Add("Medication $ " + medical);

            // Display the amount for surgical
            listBox1.Items.Add("Surgical $ " + surgical);

            // Display the amount for lad fees
            listBox1.Items.Add("Lab fees $ " + lab);

            // Display the amount for rehab
            listBox1.Items.Add("Rehab $ " + rehab);
           
        }

        private void exitButton_Click(object sender, EventArgs e)
        {
            // Close this form.
            this.Close();
        }
    }
}

Thank you so much Vulpes.  I had to make some small changes
I added a list box cuz i need to show the medication, surgical, lab and rehab fee there.
so that would look lke:

Medication $1
Surgical $1
Lab $1
Rehab $1

also I called the MiscCharge method so I could display it in one textlabel.

1. Why do you use "n2" in the code instead of 'n1'

2.The only problem is I cant display the result for the stay in one label. Look at the pic and see, the stay charges label isnt showing the result:



the code now looks like:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Hospital_Charges
{
  public partial class Form1 : Form
  {
  public Form1()
  {
  InitializeComponent();
  }

  // These methods accept the number of days at the hospital
  // and medical charges as arguments and return the
  // equivalent total of charges.
  private double CalcStayCharges(double days)
  {
  return days * 350.0;
  }

  private double CalcMiscCharges(double medical, double surgical, double lab, double rehab)
  {
  return (medical + surgical + lab + rehab);
  }

  private double CalcTotalCharges(double days, double medical, double surgical, double lab, double rehab)
  {
  return CalcStayCharges(days) + CalcMiscCharges(medical, surgical, lab, rehab);
  }

  private void calculateButton_Click(object sender, EventArgs e)
  {
  // Variables to hold the number of days spent at the hospital, amount of medication, surgical, lab and rehab charges.
  double days, stayTotal, medical, surgical, lab, rehab, totalFees, totalCharges;

  // Get the number of days.
  if (!double.TryParse(daysTextBox.Text, out days) || days <= 0.0)
  {
  MessageBox.Show("Length of stay (days) is invalid. Please enter a valid number");
  daysTextBox.Focus();
  return;
 
  }

  // Get the medication charges

  if (!double.TryParse(medicationTextBox.Text, out medical) || medical < 0.0)
  {
  MessageBox.Show("Medication charges are invalid. Please enter a valid number");
  medicationTextBox.Focus();
  return;
  }

  // Get the surgical charges

  if (!double.TryParse(surgicalTextBox.Text, out surgical) || surgical < 0.0)
  {
  MessageBox.Show("Surgical charges are invalid. Please enter a valid number");
  surgicalTextBox.Focus();
  return;
  }

  // Get the lab fees

  if (!double.TryParse(labTextBox.Text, out lab) || lab < 0.0)
  {
  MessageBox.Show("Lab fees are invalid. Please enter a valid number");
  labTextBox.Focus();
  return;
  }

  // Get the physical rehabilitation charges

  if (!double.TryParse(rehabTextBox.Text, out rehab) || rehab < 0.0)
  {
  MessageBox.Show("Phycial rehabilitation charges are invalid. Please enter a valid number");
  rehabTextBox.Focus();
  return;
  }

  // Display the stay charge.
  totalStayLabel.Text = stayTotal.ToString("n2");  

(Why isnt this working)

  // Calculate the total charges.
  totalCharges = CalcTotalCharges(days, medical, surgical, lab, rehab);
  // Display the total charges.
  totalLabel.Text = totalCharges.ToString("n2");


  // Calculate the other fees.
  totalFees = CalcMiscCharges(medical, surgical, lab, rehab);
  // Display the total Fees.
  miscLabel.Text = totalFees.ToString("n2");


  // Display the amount for medical
  listBox1.Items.Add("Medication $ " + medical);

  // Display the amount for surgical
  listBox1.Items.Add("Surgical $ " + surgical);

  // Display the amount for lad fees
  listBox1.Items.Add("Lab fees $ " + lab);

  // Display the amount for rehab
  listBox1.Items.Add("Rehab $ " + rehab);
 
  }

  private void exitButton_Click(object sender, EventArgs e)
  {
  // Close this form.
  this.Close();
  }
  }
}