i need help with programing C#

it only show the highest sale, but the lowest and averge is not working

here are the codes i wrote:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.IO;

namespace user_Lab

{

public partial class DisplaySales : Form

{

public DisplaySales()

{

InitializeComponent();

}

//open and read the text file

private void ProcessSalesFile()

{

//part1

try

{

///decalre variables

const int SIZE = 7;

double sum = 0;

double[] myArray = new double[SIZE];

int index = 0;

StreamReader inputFile;

//2.open the file to read

inputFile = File.OpenText("sales.txt");

//loop through the file to get each value a put in an array

while (!inputFile.EndOfStream && index

{

//read value into array

myArray[index] = double.Parse(inputFile.ReadLine());

//sum it all up

sum += myArray[index];

SaleslistBox.Items.Add(myArray[index].ToString("c"));

index++;

}

//3.close the file

inputFile.Close();

//call the methods.part2

highestlabel.Text = GetHighest(myArray).ToString("c");

lowestlabel.Text = Getlowest(myArray).ToString("c");

averlabel.Text = GetAverage(myArray).ToString("c");

//loop through the array to calculate the total in this loop also display each array value to the list box

totalSaleslabel.Text = sum.ToString("c");

}

catch(Exception ex)

{

// error message showing to the user

MessageBox.Show(ex.Message);

}

}

// GetHighest Method

private double GetHighest(double[] myArray)

{

double hVal = 0;

for (int count = 0; count

{

if (myArray[count] > hVal)

{

hVal = myArray[count];

highestlabel.Text = hVal.ToString("c");

}

}

//return highest

return hVal;

}

//Get lowest method

private double Getlowest(double[] myArray)

{

double low = 0;

for (int count = 0; count

{

if (myArray[count]

{

low = myArray[count];

lowestlabel.Text = low.ToString("c");

}

}

//return the lowest method

return low;

}

//write the methods GetAverage

private double GetAverage(double[] myArray)

{

double total = 0; double myAverage = 0;

for (int count = 0; count

{

myAverage = total / myArray.Length;

averlabel.Text = myAverage .ToString("c");

}

return myAverage;

}

private void GetSalesbutton_Click(object sender, EventArgs e)

{

ProcessSalesFile();

}

private void Clearbutton_Click(object sender, EventArgs e)

{

highestlabel.Text="";

averlabel.Text = "";

lowestlabel.Text = "";

totalSaleslabel.Text = "";

SaleslistBox.Items.Clear();

}

private void Exitbutton_Click(object sender, EventArgs e)

{

this.Close();

}

}

}

Sales Analysis $1,245.67 S1.189.55 $1,098.72 $1,456.88 $2,109.34 $1.987.55 $1,872.36 Highest Sale $2,109.34 Lowest Sale S0.00 Average Sale 0.00 Total Sale is $10,960.07 Get Sales Exit