Can't figure out why grade calculation isn't performed right

Question

My problem is that when I try to calculate the grade with assignments where there is less than 25/25 the grade goes to 75%. Disregarding any other points in my section.

So if every assignment has 100% on I get:

Grade   A
Percentage  105%
Labs    250 / 250

But when 1 point out of labs is missing:

Grade   C
Percentage  75%
Labs    249 / 250

Why would that be? I'm bit confused with this.

This is how I gather input from my text fields. Every text field is calling this: AutoPostBack="True" OnTextChanged="textbox_TextChanged".

    foreach (Control control in Page.Controls)
    {
        foreach (Control textbox in control.Controls)
        {
            if (textbox is TextBox)
            {
                TextBox tb = textbox as TextBox;

                char type = tb.ID.ToCharArray()[0];

                if (!string.IsNullOrWhiteSpace(tb.Text))
                {
                    if (type == 'l')
                    {
                        int outtt;
                        string inn = tb.Text;
                        Int32.TryParse(inn, out outtt);

                        labs += outtt;
                        labPoints += 25;
                    }
                    else if (type == 'q')
                    {
                        ...
                    }
                    ...
                }
            }
        }
    }

This is how I calculate the percentage:

        percent = (((labs / labPoints) * 0.3) + // labs
                ((quizzes / quizPoints) * 0.1) + // quizzes
                ((exams / examPoints) * 0.3) + // exams
                ((project / projectPoints) * 0.2) + // project
                ((extra / extraPoints) * 0.05) + // extra credit
                ((part / partPoints) * 0.10)) * 100;// participation

Answer 1

You are using integer division, which will always result in an integer. For a quick and dirty fix you should cast your variables to some floating point variables when you divide them.

e.g.:

(double)labs / (double)labPoints

(If any of the arguments is a double then the result will be a double.)