|From KC Multimedia
and Design Group...
JRPNtm - the Javatm Scientific Calculator
Version 1.1.2 - March 20, 1999
Version 1.1.2 addresses some MRJ 2.1 (Apple) specific issues. For Windows, JRPN is now bundled with JDK 1.1.7, which corrects a bug involving cut/paste to the system clipboard under NT.
JRPN is a pop-up 35-function virtual scientific calculator that uses the Reverse Polish Notation method for data entry. Unlike an algebraic calculator which has an "equals" button, a Reverse Polish Notation (RPN) calculator does not use an "equals" key. Hewlett-Packard handheld calculators are the best-known examples using RPN. Most RPN users consider it to be faster and superior to algebraic data entry.
JRPN features continuous (file-based) "memory" and 10 persistent storage registers. Styled to look like a calculator, JRPN responds to either keyboard or mouse input. JRPN also supports copying calculated values into the system clipboard for pasting into some other application on the desktop.
JRPN requires a Java 1.1.7 runtime. For Windows, we include the necessary Java runtime in the download file. On the Mac, you must have Apple's MRJ 2.1 installed.
It's easy and logical. The calculator works with an internal register stack. When you enter numbers, you push operands onto the stack, When you press an operator, it operates on the numbers in the stack.
For example, let's add two numbers, 125 and 312. Key in 125 and press ENTER. Key in 312 and press '+'. The answer, 437 is displayed. Now to subtract 37, simply key in 37 and press '-'. The answer, 400, is displayed. Notice that we have used one less keystroke in this simple example than would have been required with an algebraic calculator with an '=' key. The stack makes it easy to perform chained calculations.