/// <summary>
        /// calculate the 1 rep max bench
        /// </summary>
        private void btn_CalculateMaxBench_Click(object sender, EventArgs e)
        {
            double weight = 0;
            double value;
            double maxWeight;
            int    maxBench;
            int    reps = 0;
            string validationFeedback;
            string userMessage = null;
            string unit        = "lbs";

            //
            // assign max weight values based on selected button
            //
            if (radBtn_Lbs.Checked == true)
            {
                maxWeight = MAX_WEIGHT_LBS;
            }
            else
            {
                maxWeight = MAX_WEIGHT_KG;
                unit      = "Kg";
            }

            //
            // validate user input weight and build out the feedback message
            //
            if (!ValidateUserInput(txtBox_weight.Text, maxWeight, out value, out validationFeedback))
            {
                userMessage       += "The Weight" + validationFeedback + Environment.NewLine;
                txtBox_weight.Text = null;
            }
            else
            {
                weight = value;
                reps   = (int)btn_numReps.Value;
            }


            if (userMessage != null)
            {
                //lbl_ErrorMessage.Text = userMessage;
                MessageBox.Show(userMessage);
            }
            //
            // open the SolutionForm
            //
            else
            {
                maxBench = MaxBench(weight, reps);

                Form solutionForm = new form_Solution(new SolutionFormInfo(maxBench, unit));
                solutionForm.FormBorderStyle = FormBorderStyle.FixedDialog;
                solutionForm.MaximizeBox     = false;
                solutionForm.MinimizeBox     = false;
                solutionForm.ShowDialog();
                solutionForm.Dispose();
            }
        }
        /// <summary>
        /// calculate the number of people who fit
        /// </summary>
        private void btn_CalculatePeople_Click(object sender, EventArgs e)
        {
            double length = 0, width = 0, height = 0;
            double value;
            double maxDimension;
            int    numberOfPeople;
            string validationFeedback;
            string userMessage = null;

            //
            // validate dimensions and return values
            //
            if (radBtn_English.Checked == true)
            {
                maxDimension = MAX_DIMENSION_FT;
            }
            else
            {
                maxDimension = MAX_DIMENSION_M;
            }

            //
            // validate each user input and build out the feedback message
            //
            if (!ValidateUserInput(txtBox_Length.Text, maxDimension, out value, out validationFeedback))
            {
                userMessage       += "The Length" + validationFeedback + Environment.NewLine;
                txtBox_Length.Text = null;
            }
            else
            {
                length = value;
            }
            if (!ValidateUserInput(txtBox_Width.Text, maxDimension, out value, out validationFeedback))
            {
                userMessage      += "The Width" + validationFeedback + Environment.NewLine;
                txtBox_Width.Text = null;
            }
            else
            {
                width = value;
            }
            if (!ValidateUserInput(txtBox_Height.Text, maxDimension, out value, out validationFeedback))
            {
                userMessage       += "The Height" + validationFeedback + Environment.NewLine;
                txtBox_Height.Text = null;
            }
            else
            {
                height = value;
            }

            if (userMessage != null)
            {
                //lbl_ErrorMessage.Text = userMessage;
                MessageBox.Show(userMessage);
            }
            //
            // open the SolutionForm
            //
            else
            {
                numberOfPeople = NumberOfPeople(length, width, height);

                Form solutionForm = new form_Solution(new SolutionFormInfo(numberOfPeople, cmbBox_BodyType.Text));
                solutionForm.FormBorderStyle = FormBorderStyle.FixedDialog;
                solutionForm.MaximizeBox     = false;
                solutionForm.MinimizeBox     = false;
                solutionForm.ShowDialog();
                solutionForm.Dispose();
            }
        }