Scientific Calculator

Overview

A native Android scientific calculator whose maths engine is written from scratch. Instead of handing expressions to a third-party eval library, it parses and evaluates them itself with a hand-written recursive-descent parser.

What We Built

• Full scientific function set: sin, cos and tan (plus inverse and hyperbolic versions), ln, log and log2, square and cube roots, powers, factorial and 1/x
• Degrees and radians toggle
• Constants: π and e
• Material Design interface using View Binding

Engineering Highlights

• A real expression parser. It follows standard operator precedence: ^ binds tighter than × and ÷, which bind tighter than + and −. It fully supports parentheses and unary minus.
• Clean grammar. From highest to lowest precedence: primary → unary → pow → mulDiv → addSub, with parenthesised sub-expressions handled recursively.
• No eval shortcut. Writing the evaluator by hand means every result is predictable and testable, with no hidden library behaviour.

Tech Stack

Kotlin, Android View Binding and Material Components.

Status

Open source under the MIT licence at github.com/mukeshkumar356/scientific-calculator.