Java Console Calculator

A console-based calculator application built in Java.

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Project Description

This project implements a feature-rich console-based calculator using Java. It demonstrates:

• Object-Oriented Programming (OOP) principles
• Clean code structure with separation of concerns
• Meaningful Git commit history and version control practices

The calculator supports arithmetic operations, keeps a session history, and provides a clean, color-coded terminal interface.

Note: All the results are displayed to 4 decimal places for consistency (e.g. 120 displays as 120.0000). This makes sure that there is uniform formatting across both whole numbers and decimal results.

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Features

Feature	Description
➕ Addition	Add two numbers
➖ Subtraction	Subtract one number from another
✖️ Multiplication	Multiply two numbers
➗ Division	Divide with zero-division error handling
% Modulus	Find the remainder of division
^ Power	Raise a number to an exponent
√ Square Root	Compute the square root (with negative guard)
History	View all calculations made in the current session
Clear	Reset history and last result

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Project Structure

java-calculator/
├── src/
│   └── calculator/
│       ├── Main.java           # Entry point & CLI interface
│       └── Calculator.java     # Core arithmetic logic
├── .gitignore
└── README.md

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⚙️ Prerequisites

Requirement	Version
Java JDK	17+

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How to Run

1. Clone the Repository

git clone https://github.com/ThatoMabilo/java-calculator.git
cd java-calculator

2. Compile the Source Files

javac -d out src/calculator/Main.java src/calculator/Calculator.java

3. Run the Application

java -cp out calculator.Main

4. Using the Calculator

Once launched, you'll see a menu like this:

  ── Operations ─────────────────────────
  1  Addition          (+)
  2  Subtraction        (-)
  3  Multiplication     (*)
  4  Division           (/)
  5  Modulus            (%)
  6  Power              (^)
  7  Square Root        (√)
  ── Utilities ────────────────────────────
  8  Show Last Result
  9  Show History
  0  Clear History
  q  Quit

Enter the number of the operation you want, then enter your numbers when prompted.

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Screenshots

Screenshots of the application running on my local machine are available in the /screenshots folder of this repository.

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Example Session

  Enter choice: 1
  Enter first number : 15.5
  Enter second number: 4.5

  15.5000  +  4.5000  =  20.0000

  Enter choice: 6
  Enter first number : 2
  Enter second number: 10

  2.0000  ^  10.0000  =  1024.0000

  Enter choice: 9

  ── Calculation History ──
  15.0000 + 4.5000 = 20.0000
  2.0000 ^ 10.0000 = 1024.0000

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Git Commit History

This project follows a structured commit strategy:

Commit	Description
init	Initial project scaffold and README
feat	Add Calculator core logic (all operations)
feat	Add Main CLI with color-coded menu
fix	Handle edge cases (div by zero, negative sqrt)
docs	Update README with usage instructions

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Author

• Student: Thato Anikie Mabilo
• Student Number: 222148349
• Lecturer: Dr. Boniface Kabaso
• Program: Console-based Calculator

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