Binary Converter 🔢

A command-line tool that converts decimal numbers (including fractions) to binary representation. Built with Node.js using recursion and implementing proper mathematical conversion algorithms.

📖 About The Project

This CLI application converts decimal numbers to binary format using mathematical algorithms implemented through recursive functions. It handles both integers and fractional decimal numbers, demonstrating core programming concepts like recursion, input validation, and number system conversion.

What Makes This Special

✅ Handles Integers AND Fractions - Not just whole numbers
✅ Pure Recursion - Mathematical algorithms implemented recursively
✅ Input Validation - Checks for valid decimal numbers
✅ Educational - Clean code demonstrating recursion concepts

🎯 Features

🔄 Recursive Conversion - Uses mathematical recursion for both integer and fractional parts
🔢 Decimal to Binary - Accurate conversion of decimal numbers
💯 Fraction Support - Converts decimal fractions (e.g., 5.75 → 101.11)
✅ Input Validation - Prevents invalid inputs (negative numbers, non-numbers, empty strings)
🎨 Clean CLI Interface - Simple and straightforward user experience
📚 Educational Code - Clear implementation of conversion algorithms

📸 Demo

$ node app.mjs

Enter the number: 10
You have entered 10
The binary equivalent of 10 is: 1010

$ node app.mjs

Enter the number: 5.75
You have entered 5.75
The binary equivalent of 5.75 is: 101.11

$ node app.mjs

Enter the number: -5
Please input a decimal number greater than 0
Enter the number: 12.5
You have entered 12.5
The binary equivalent of 12.5 is: 1100.1

🧮 How Binary Conversion Works

Integer Conversion

The algorithm divides the number by 2 repeatedly and keeps track of remainders:

Example: 10 (decimal) → 1010 (binary)
10 ÷ 2 = 5 remainder 0
5 ÷ 2 = 2 remainder 1
2 ÷ 2 = 1 remainder 0
1 ÷ 2 = 0 remainder 1
Reading remainders from bottom to top: 1010

Fraction Conversion

The algorithm multiplies the fraction by 2 repeatedly and tracks the integer part:

Example: 0.75 (decimal) → 0.11 (binary)
0.75 × 2 = 1.5 → integer part: 1, fraction: 0.5
0.5 × 2 = 1.0 → integer part: 1, fraction: 0.0
Reading integer parts: 0.11

🛠️ Built With

Node.js - JavaScript runtime
ES6 Modules (.mjs) - Modern JavaScript syntax
prompt-sync - User input handling
Recursion - Core algorithm implementation

📋 Prerequisites

Node.js (v12.0.0 or higher)
npm (Node Package Manager)

Check your installation:

node --version
npm --version

🚀 Installation & Setup

1. Clone the Repository

git clone https://github.com/rishiverma12031/BinaryConverter.git
cd BinaryConverter

2. Install Dependencies

npm install prompt-sync

3. Run the Converter

node app.mjs

💻 Usage

Run the application: node app.mjs
Enter a decimal number when prompted (positive numbers only)
View the binary result displayed in the terminal

Valid Inputs

Whole numbers: 10, 255, 1024
Decimal fractions: 5.5, 12.75, 0.625
Zero: 0

Invalid Inputs (Will prompt for re-entry)

Negative numbers: -5
Non-numeric values: abc, 12a
Empty input:

📁 Project Structure

BinaryConverter/
│
├── app.mjs              # Main application file
├── package.json         # Project dependencies (create this)
└── README.md           # Documentation

🔧 Code Structure

Main Functions

`convertToBinary(decimalNum)`

Main conversion function
Splits number into integer and fractional parts
Combines binary results from both parts

`convertToBinaryInteger(decimalNum)`

Recursive function for converting integer part
Base case: Returns when number is 0 or 1
Recursive case: Divides by 2 and processes remainder

`convertToBinaryFraction(decimalNum)`

Recursive function for converting fractional part
Base case: Returns when fraction becomes 0
Recursive case: Multiplies by 2 and tracks integer part

`checkInputValue()`

Validates user input
Checks for negative numbers, NaN, and empty strings
Recursive - Re-prompts on invalid input

🎓 Learning Outcomes

This project demonstrates understanding of:

Core Concepts

✅ Recursion - Multiple recursive functions with proper base cases
✅ Number Systems - Understanding binary and decimal conversion
✅ Mathematical Algorithms - Implementing standard conversion methods
✅ Type Coercion - String/Number conversions and type handling
✅ Input Validation - Using isNaN(), comparison operators
✅ String Manipulation - split(), String() conversions
✅ ES6 Modules - Modern import/export syntax

Programming Practices

Clean function separation
Recursive algorithm design
Error handling and validation
User-friendly CLI interface

🧪 Test Cases

Try these inputs to test the converter:

Decimal	Expected Binary	Description
0	0	Zero
1	1	One
10	1010	Simple integer
255	11111111	8-bit max value
0.5	0.1	Simple fraction
0.75	0.11	Three-quarters
5.75	101.11	Mixed number
12.5	1100.1	Decimal with .5

🔬 Algorithm Explanation

Integer Part (Division Method)

function convertToBinaryInteger(decimalNum) {
    // Base case: 0 or 1 can't be divided further
    if (decimalNum === 0 || decimalNum === 1) return String(decimalNum);
    
    // Recursive case: divide by 2 and concatenate remainder
    return convertToBinaryInteger(Math.floor(decimalNum / 2)) + String(decimalNum % 2);
}

How it works:

Divide number by 2 using Math.floor() for integer division
Get remainder using modulo operator %
Recursively process quotient
Concatenate remainders in reverse order

Fractional Part (Multiplication Method)

function convertToBinaryFraction(decimalNum) {
    // Base case: fraction becomes 0
    if(decimalNum === 0) return String(decimalNum);
    
    // Recursive case: multiply by 2 and track integer part
    return String(Math.floor(decimalNum * 2)) + 
           convertToBinaryFraction(decimalNum * 2 - Math.floor(decimalNum * 2));
}

How it works:

Multiply fraction by 2
Extract integer part (0 or 1) using Math.floor()
Get new fraction part (remainder after extracting integer)
Recursively process new fraction
Concatenate results in order

🎨 Customization Ideas

Easy Modifications

Add support for other number bases (octal, hexadecimal)
Display step-by-step conversion process
Add option to convert binary back to decimal
Implement iterative versions alongside recursive

Medium Challenges

Add command-line arguments for batch conversion
Output conversion steps for educational purposes
Support multiple number formats as input
Add file input/output for bulk conversions

Advanced Features

Create a GUI version with Electron
Add support for negative numbers (two's complement)
Implement scientific notation support
Build a web version with conversion visualization

🐛 Troubleshooting

Common Issues

Error: "Cannot find module 'prompt-sync'"

npm install prompt-sync

Error: "SyntaxError: Cannot use import statement outside a module"

Ensure file extension is .mjs, OR
Add "type": "module" to package.json

Infinite loop with fractions

This occurs with repeating binary fractions (like 0.1 decimal)
Consider adding a precision limit in production code

Input validation not working

Check that isNaN() is used correctly
Ensure comparison operators are appropriate (< for negative check)

🌟 Future Enhancements

🤝 Contributing

Contributions are welcome! Here's how:

Fork the project
Create your feature branch (git checkout -b feature/AmazingFeature)
Commit your changes (git commit -m 'Add AmazingFeature')
Push to the branch (git push origin feature/AmazingFeature)
Open a Pull Request

📝 License

This project is open source and available under the MIT License.

👤 Author

Rishi Verma

GitHub: @rishiverma12031
Project Link: https://github.com/rishiverma12031/BinaryConverter

🙏 Acknowledgments

Built to learn and practice recursion and mathematical algorithms
Implements standard decimal-to-binary conversion methods
Uses prompt-sync for user input

📚 Resources & References

💡 Educational Note

While JavaScript provides Number.toString(2) for binary conversion, this project implements the algorithm from scratch using recursion to demonstrate:

How recursion solves mathematical problems
Understanding of number system conversion
Implementation of standard conversion algorithms
Practical application of recursive thinking

Ready to convert? Run node app.mjs and start converting! 🔢

Built with ❤️ while learning recursion and mathematical algorithms in JavaScript

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