calc

This is a C implementation of an operator-precedence parser to evaluate mathematical equations.

Usage

The program executes the mathematical expression passed in via argv or stdin:

$ calc "1+2"
3

$ echo "1+2" | calc
3

Alternatively running the program without arguments enables REPL mode:

$ calc                                                                                                                                
= 1+2
3
= ans+5
8

Supported Operators

Operator	Description
+	Addition
-	Subtraction / Unary Negative
/	Division
*	Multiplication
(	Left Parenthesis
)	Right Parenthesis

Supported Variables

Name	Description
ans	Previously Calculated Answer

Caveats

• No support for non-integer math
• No support for creating variables
• No builtin functions
• No history buffer