I need some help. I want to be able to put in a letter grade within a textbox of a class and have the program know that A is 4.0 (A=4.0) then calculate the GPA by adding all the class grades and dividing by seven which is the number of classes which equals the GPA.

This is what it looks like:

http://img159.imageshack.us/img159/3107/gpacalcgy7.png

A = 4.0
A- =3.7
B+ = 3.3
B = 3.0
B- =2.7
C+=2.3
C=2.0
C-=1.7
NG = 0



My code looks like this so far it just doesn't know how to interpret A as 4.0 and calculate the GPA:



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

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

        private void label1_Click(object sender, EventArgs e)
        {

        }

        private void label4_Click(object sender, EventArgs e)
        {

        }

        private void textBox8_TextChanged(object sender, EventArgs e)
        {

        }


        private void button1_Click(object sender, EventArgs e)
        {
            int x = 0;


            try
            {

                double g1 = Convert.ToDouble(textBox1.Text);
                double g2 = Convert.ToDouble(textBox2.Text);
                double g3 = Convert.ToDouble(textBox3.Text);
                double g4 = Convert.ToDouble(textBox4.Text);
                double g5 = Convert.ToDouble(textBox5.Text);
                double g6 = Convert.ToDouble(textBox6.Text);
                double g7 = Convert.ToDouble(textBox7.Text);
                textBox8.Text = Convert.ToString((g1 + g2 + g3 + g4 + g5 + g6 + g7) / 7.0);



            }
            catch
            {
                Console.Write(textBox8.Text = "ERROR");
                Console.Beep(x = 266, x = 300);
            }

        }
        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button2_Click(object sender, EventArgs e)
        {
            Close();
        }
    }
}



If you could help me on this it would be greatly appreciated. :)

You just need to write a method which takes a string and returns a double and inside has a big switch statement..

e.g.

public double ConvertGpa(string grade)
{
  switch(grade)
  {
    case "A":
      return 7.0;
    case "B":
      return 6.0;
    etc...

   default:
     throw Exception("Unknown grade");
  }
}

/- Sam Judson : Wrox Technical Editor -/