Listing 1

/***************************************************************
 *       CGIGet is a routine we extracted from the NCSA        *
 *       routine post-query.c, by Rob McCool.  We'll go into   *
 *       this routine in greater detail next issue.  For now,  *
 *       simply be aware that it returns a pointer to a string *
 *       containing the value for the variable requested, or   *
 *       NULL if the variable didn't have a value.             *
 ***************************************************************
*/

   // Get the selected challenge
	Selected = CGIGet("Select");
	if (Selected != NULL)
		iSelected = atoi(Selected);
	else
		{
		show_error_screen(sPageInfo, "You have not selected a
challenge.  Please select a challenge and try again.");
		iSelected = 0;
		return 0;
		}

   // Figure out which button was hit and process it.
   // SELCT1 is the name of the bitmap.  We gave it that name in the
   // <INPUT TYPE=IMAGE NAME=> tag.  Because it is a bitmap,
   // the browser returns the X and Y coordinates of the hit.  Since
   // we're only interested in the X (Horizontal) position, we don't
   // check the Y value.

	cXpos = CGIGet("SELCT1.x");
	if (cXpos != NULL)
		{
		// Convert the char to an integer
		sscanf(cXpos, "%d", &Xpos);

		if (Xpos < 75)
			{
			// User hit the first button (Play)
			.
			.
			Code to start playing a challenge
			.
			.
			}
		else if (Xpos < 150)
			{
			// User hit the second button (Details)
			.
			.
			Code to show the challenge details
			.
			.
			}
		else if (Xpos < 225)
			{
			// User hit the third button (Delete)
			.
			.
			Code to remove a player from a challenge
			.
			.
			}
		else if (Xpos < 300)
			{
			// Display the login page 
			show_user_login(sPageInfo);
			}
		else
			{
			// Help screen
			sPageInfo->iCurrentChallenge = iSelected;
			iSelChlng = iSelected;
			WriteItAll(sPageInfo);
			show_help_screen(sPageInfo);
			}
		}

Figure 2