The GRASS Calculator¢¢by Gary Heitz¢¢ The GRASS Calculator was created as part of the Grand Rapids Atari System Supporters' BASIC programming class. We started by explaining cursor controls and simple PRINT and POSITION statements.¢ A simple calculator was used to demonstrate these commands and to explain the math operations. As time went by, the simple calculator became more involved and grew as new features were added.¢ One unusual feature that was included affected how the calculator's memory worked. On a normal calculator, you store something in memory but unless you have a pretty good memory yourself, you can easily forget what you stored there. The GRASS Calculator has two number displays. One is like that on any calculator -- the main display. The second one always shows what has been stored in the memory.¢ The other features of the GRASS Calculator are:¢¢Print - will print to a printer just like a more expensive printing calculator will do.¢¢Change decimal places - will either display your number normally with no alterations to any decimal places, or it will round the number's decimal places to the nearest hundredths.¢¢Change signs - This feature is like the +/- key on most calculators. It will change the current number from positive to negative or vice versa.¢¢Four memory keys - Memory + (add to memory), Memory - (subtract from memory), Memory (display the contents of memory in the main display), and Memory Clear (clears the memory).¢¢Clear and All Clear - Clear erases the number you are currently entering (good for when your finger goes a little crazy on you and hits the wrong key). All Clear will clear everything in the main display. It does not clear the memory, though.¢¢Root and Square Root¢¢Decimal to Hexadecimal Conversions¢¢Hexadecimal to Decimal Conversions¢¢Percent - This will convert a number into its percent.¢¢Quit - I added this feature because it allows for a clean exit from the calculator without having to hit the RESET button.¢¢ Because the GRASS Calculator is not just for adults with perfect coordination, which does not include myself, I have added some "safety" features. The BREAK key will not work. The two other keys that will get you nowhere are the Atari, or inverse, key and the Caps key. If you hit one of these keys by accident, there is no need to worry; they will be ignored.¢ Here's an idea for any BASIC programmers out there or anyone interested. If you renumber this program to begin with a high line number, like 30000, you can do your programming and GOTO the first line of the calculator to use it and QUIT when you are done with your calculations. This way you don't have to keep loading and reloading the program you are working on.¢ One last thing to mention. The two inverse letters that precede each line in the type in program are checksums. They work the same as any BASIC program that you find in Antic or ANALOG. You can use either of their type in programs to type in the GRASS Calculator.¢ I hope you enjoy using it.¢¢END.¢
