HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 263

We'll now create the associated 'helper' programs (shown below). Their names/titles are supplied above the code for each one. A short explanation is given. For more information on the various commands see the chapter "Programming Commands" on page 281. .MSG.2 .MSG.1 .MSG.IN ERASE clears the screen, ready The MSGBOX command is The INPUT command asks the user to DISP a message on lines 4 used to display the traditional for info, displaying a title, prompt and 5 of the screen. The first message for programmers and tip and having a default value calculator then FREEZEs waiting learning a new language! of 20. You could use the PROMPT for a key to be pressed. command instead but INPUT is more flexible. .MSG.FN .MSG.S .MSG.SV This is the most complex of the programs. See right for an explanation. Puts an initial message up. The command GROB in the program left, stands for "Graphic Object" and creates a GROB from the F1(X) expression stored in the The SETVIEWS command is discussed in detail on the previous pages. SYMB view, storing it in the graphic memory G1, using the font specified (0, 1, 2 or 3). The reason for doing it this way is to use proper mathematical layout like SHOW does. The DISPLAY command then shows it on screen. This is repeated a number of times with different fonts. Finally, a line and box are drawn on the screen. There are more explanations later of all this. 263