## New improved Reverse Polish Notation calculator

Visit the Downloads page for the full source code and executable version.

What's new in version 3?
* COPY command added.  Copies the accumulator to the Windows Clipboard.
* ACC ON/ACC OFF comands added.  Turning on forces the accumulator not to clear after a calculation.  The following result is added to the accumulator following each calculation.
* HEX/DEN/BIN/OCT commands added to switch between base 16, base 10, base 2 and base 8.
* LAST special variable added which stores the current value of the accumulator, allowing the previous result to be treated as a variable in proceeding calculations.
* INV function added.  Returns 1/x where x is the argument.

## New Improved Little Man Computer

Following some user feedback with a class of students following the OCR GCSE Computing low-level programming module (A451), I have made the following improvements to the Little Man Computer Simulator:

LMC version 1.0.0.5

• Scroll-bars have been added to the input window.
• Lower-case input is accepted (the LMC is not case-sensitive, so 'y' and 'Y' are same label name).
• Improved step-through mode (there is now time to click the mouse to halt the program)

## Reverse Polish Notation Calculator in BBC BASIC for Windows

A BBC BASIC for Windows implementation of a simple RPN Calculator.  We've just finished version 1.01 and is available to download from here.

Reverse Polish notation is a parenthesis-free algebraic notation, known as post-fix notation.  We are all familiar with standard algebraic notation (or in-fix notation):

`(1 + 2) * 3`  < in-fix notation >

In RPN, this is expressed:

`1 2 + 3`  *  < post-fix notation >

The parentheses are used to avoid ambiguity over the order of operations (often taught as BODMAS in school).  For example, the first expression could be confused with the literal expression `1 + (2 * 3)` which would give a different result.  Parentheses are not required in post-fix notation.  For example, `1 + ( 2 * 3 )` is expressed as:

`1 2 3 * +`