General Description
The program displays the periodic table of the elements, in various groupings, with full categorisation of the element types, which both distinguishes it from simpler and shorter programs merely listing the elements, and accounts for the length of the program generally, with the multiple data lists such a categorisation requires. The program first presents a menu to the user, to allow a choice of the main display groupings, and the two test routines included in the program. Subsidiary menus are presented in the procedures accessed from the main menu to allow further choice of groupings and periods. The presentation of the elements in coloured tabular form makes them clear and easy to understand and remember.
The program as it stands, with full remark statements and the necessary spacing around the REMs to render the listing reedable, will not run on a Model A, but will fit if you remove all remarks and cut down the variable names, which again are there for clarity. Note however that the PRINT statements are run together in places to fit the screen, so type the statements exactly as they appear in the listing.
The BREAK and ESCAPE keys are trapped in this program, but the auto-repeat is left connected, and the keyboard buffer is not flushed. This has implications for the test sections of the program, but allows quick scanning elsewhere in the program.
Detailed Description
Lines 10-250 Main program section calling routines selected from menu display.
260-1740 These procedures initialise the program, display titles and the instructions (when requested from the menu), and provide the data for the program. Great care must be exercised to ensure the data is typed in correctly. The 999 which appears in the data statements after line 1420 acts as a data terminator, but the trailing zeroes are needed to prevent the READ statements in lines 660-700 from failing.
1750-2100 These lines contain the menu procedure, and the text display for the routines to display elements by periodic groupings, with a subsidiary menu for the choice of period. Note the keyboard validations in lines 1910-1960 and 2060-2080.
2110-2800 These lines have the procedure for display of chosen periods of the elements.
2810-3680 Procedures to display particular groups of elements as chosen in lines 3130-3160.
3690-end This sections contains the test sections of the program. The conversion routine in lines 4100-4160 means the program will accept answers both in lower and upper case. The correct answers are displayed when you have finished the test. Both tests are 20 questions at random.
Educational Note
These types of programs are good exercises in information retrieval for upper school youngsters. There is nothing in the program which cannot be found in a book, but the presentation in groupings and periods and the very interaction with the computer has tutorial value. The level of knowledge assumed is good O-level or A-level, and below this standard youngsters will not find it very meaningful. It provides a good quick reference for teachers, but must of course be located before it is needed to fulfil this function.