RPN-calc
A console-based Reverse Polish Notation calculator written in C.
Setup
Compile with gcc using make, then run the rpn executable.
Run rpn -h or rpn -? for help.
Features
The calculator supports the 4 basic floating-point (double precision) operations, as well as exponentiation: +, -, *, /, ^. The number of decimal digits in the output can be modified with the -p option (2 by default). Memory operations can be performed using m+, m-, mr, mc operators (the m character can be substituted using the -m option).
By default, the calculator works with stdin & stdout. It is able to process file input & output, which can be configured using the -i, -o options. When the # character is found in the input (can be modified with the -c option), processing of the current line is finished, which allows for comments when working with files. The $ character (modifiable via -q) can be used to quit the app.
For no good reason, the calculator can be configured to treat a character other than space as whitespace. To do that, use the -w option. To add to the insanity, x can be used mid-calculations to force-clear the stack (likewise modifiable with -d).