C#

Price    .10      .15      .20      .25
--------------------------------------
10.00    1.00    1.50     2.00     2.25
15.00    1.50    2.25     3.00     3.25
20.00    2.00    3.00     4.00     5.00
25.00    2.50    3.75     5.00     6.25

.10   .15   .20   .25
10.00 15.00 20.00 25.00
1.00   1.50   2.00   2.25   1.50  2.25   3.00   3.25 etc.

namespace TippingTable2GUI
{
public partial class frmMain : Form
{
    public frmMain()
    {
        InitializeComponent();
    }

    private void buttonCalc_Click(object sender, EventArgs e)
    {

        double dinnerPrice = Convert.ToDouble(minPrice.Text);
        double tipRate;
        double tip;

        double maxRate = Convert.ToDouble(maxTax.Text);
        double lowRate = Convert.ToDouble(minTax.Text);
        double minDinner = Convert.ToDouble(minPrice.Text);
        double maxDinner = Convert.ToDouble(maxPrice.Text);

        const double TIPSTEP = 0.05;

        const double DINNERSTEP = 10.00;


        tipRate = lowRate;


        label1.Text = "";
        label6.Text = "";
        label7.Text = "";

        for (tipRate = lowRate; tipRate <= maxRate; tipRate += TIPSTEP)
            label1.Text = label1.Text + String.Format(" {0, 8}", tipRate.ToString("F"));
        label1.Text = label1.Text + String.Format("{0, 8}", tipRate.ToString("C"));
        const int NUM_DASHES = 50;
        for (int x = 0; x < NUM_DASHES; ++x) ;


        while (dinnerPrice <= maxDinner)
        {
            label6.Text = label6.Text + String.Format("{0, 8}", dinnerPrice.ToString("C"));
            while (tipRate <= maxRate)
            {
                tip = dinnerPrice * tipRate;
                label7.Text = label7.Text + String.Format("{0, 8}", tip.ToString("F"));
                tipRate += 0.05;
            }
            dinnerPrice += DINNERSTEP;
            tipRate = lowRate;

        }


    }
}