xpr.c

xpr.c is a mathematical expression evaluator written in pure c.

About The Project

This project was meant to be a gateway into the world of low-level computer programming. I wanted to work on a project that would introduce me to concepts such as lexical analysis & parsing, and thought that this project would be a great place to start (it was!). This project will be used as a stepping stone for future low level projects I want to work on, such as other parsers, interpreters, compilers, and languages.

Under The Hood

xpr.c is a command line application that uses a "Read-Eval-Print-Loop" interface to evaluate mathematical expressions provided by a user. The application starts off in the "Read" state which fetches a string from the user, preferably one that represents an infix expression like 2+2*(4/2*(4*2)^2). The application then moves on the the "Eval" state which will validate that the string is infact an infix expression, tokenize the string into a sequence of tokens, reoder the tokens into postfix notation using The Shunting Yard algorithm, then evaluate the postfix expression using a stack based algorithm.

Limitations

xpr.c only supports the following mathematical operators: ^ * / + -. It also does not support signed operands (coming soon!)

Getting Started

These instructions will help you get a copy of this project up & running on your machine.

Prerequisites

You must have a gcc & make installed on your machine to compile & build this project

Installation

Clone the repository to your local machine:

C:\Users\Refaat\Desktop\mathematical-expression-evaluator> git clone https://github.com/Refaat0/xpr.c .

Build the project with make:

C:\Users\Refaat\Desktop\mathematical-expression-evaluator> make

Run the program:

C:\Users\Refaat\Desktop\mathematical-expression-evaluator> xpr.exe

Usage

After running the program you will be dropped into a REPL interface. At this point you can type almost any infix expression you want such as 2+2*(4/2*(4*2)^2). Please see limitations for more details