In my dialog, there are one edit box (for input file) and two checkboxes, called "Top" and "Bottom". After the user browses the file from the directory, they have to click on one of checkboxes, in order to explain what kind of file they get, if it is "Top" file or "Bottom" file. If they click on the "Top" checkbox, there are program that go through the file and do something, or if they click on the "Bottom" checkbox, there are the same program that go through the file ans do something else. What I want to know is how to make the program to response those check boxes. So far, I already created those checkboxes, and made variable fuctions for them.
void CDesignDlg::OnTop()
{

}

void CDesignDlg::OnBottom()
{

}

I want to know what kind of code I shall put in those functions, in order to make them work.

Please help me out. Thank you very much.