RPN Calculator

A C program that takes a string which contains an equation written in Reverse Polish notation (RPN) as its first argument, evaluates the equation, and prints the result on the standard output followed by a newline.

About

Reverse Polish Notation is a mathematical notation in which every operator follows all of its operands. In RPN, every operator encountered evaluates the previous 2 operands, and the result of this operation then becomes the first of the two operands for the subsequent operator. Operands and operators must be spaced by at least one space.
See more

Algorithm explained

[TODO]

Latest Features

The folowing operator works well: "+", "-", "/", "*", "%" .

Building

The code was written on Ubuntu 18.04.4 LTS, and to compile it you'll need

• gcc
• make

make

Testing

The folder answer/ contains a list of expexted result for each test case written in ./spec.sh

sh spec.sh

Usage

The program will write "Error\n" to the stdout it the string isn't valid or there isn't exactly one argument.

All the given operands must be in INTEGER type.

$> ./rpn "1 2 * 3 * 4 +" | cat -e
10$
$> ./rpn "1 2 3 4 +" | cat -e
Error$
$> ./rpn |cat -e
Error$