{
    public partial class FuelConsumptionFrm : Form
    {
        public FuelConsumptionFrm()
        {
            InitializeComponent();
        }

        private void CalculateConsumptionBtn_Click(object sender, EventArgs e)
        {
            double dblLitres = (Convert.ToDouble(FuelTotalCostTxtBox.Text) / (Convert.ToDouble(FuelPriceTxtBox.Text) / 100));
            double dblDistance = Convert.ToDouble(CurrentOdometerTxtBox.Text) - Convert.ToDouble(PreviousOdometerTxtBox.Text);
            double dblLitresPerHundredKm = (dblLitres / dblDistance) * 100;

            ShowConsumptionLitresLbl.Text = "Consumption is " + Convert.ToString(dblLitresPerHundredKm) + " L/100km";

            double dblMilesPerGallon = FuelConsumptionMilesPerGallon(dblLitresPerHundredKm);

            ShowConsumptionMilesLbl.Text = "or " + Convert.ToString(dblMilesPerGallon) + " mpg.";

            Graphics graConsumption = KmPLGraphPicBox.CreateGraphics();
            graConsumption.Clear(Color.Gold);
            SolidBrush brsBlack = new SolidBrush(Color.Black);
            graConsumption.FillRectangle(brsBlack, (Convert.ToInt32(dblLitresPerHundredKm) * 10), 0, 5, 30);
        }

        private double FuelConsumptionMilesPerGallon(double dblLitresPerHundredKm);
        double dblMilesPerGallon = 0;
        double dblMilesPerGallon = 454.6 / (1.609 * dblLitresPerHundredKm);

    }
}