HP HP12C hp 12c_user's guide_English_E_HDPMBF12E44.pdf - Page 90

90 Section 8: Programming Basics Example: Run the program created above to calculate the net cost of a typewriter listing for $625 and an executive chair listing for $159. Keystrokes fs 625 t 159 t Display 155.00 625. 473.75 159. 124.25 Sets calculator to Run mode. Display shows number previously calculated. Keys in price of typewriter. Net cost of typewriter. Keys in list price of chair. Net cost of chair. That's all there is to creating and running simple programs! But if you want to use programs frequently, you'll want to know more about programming - such as how to check what keystrokes are stored in program memory, how many keystrokes can be stored in program memory, how to correct or otherwise modify programs, how to skip keystrokes when running a program, and so on. Before you can understand these aspects of programming, we need to briefly discuss how keystrokes are treated by the calculator when they are stored in Program mode and when they are executed in Run mode. Program Memory Keystrokes entered into the calculator in Program mode are stored in program memory. Each digit, decimal point, or function key is called an instruction and is stored in one line of program memory - usually referred to simply as a program line. Keystroke sequences beginning with the f, g, ?, :, and i prefix keys are considered to comprise a complete instruction and are stored in only one program line. When a program is run, each instruction in program memory is executed - that is, the keystroke in that program line is performed, just as if you were pressing the key manually - beginning with the current line in program memory and proceeding sequentially with the higher-numbered program lines. Whenever the calculator is in Program mode (that is, whenever the PRGM status indicator in the display is lit), the display shows information about the program line to which the calculator is currently set. At the left of the display is the number of the program line within program memory. The remaining digits in the display comprise a code that indicates what instruction has been stored in that program line. No code is shown for program line 00, since no regular instruction is stored there. File name: hp 12c_user's guide_English_HDPMBF12E44 Printered Date: 2005/7/29 Page: 90 of 209 Dimension: 14.8 cm x 21 cm