🚀 Coding Analyzer & Expression Evaluator

A full-stack web application that analyzes code complexity and evaluates mathematical expressions using core data structures.

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📌 Overview

This project demonstrates the real-world application of Data Structures (Stack) by building:

• 🔢 Expression Evaluator (Infix, Prefix, Postfix)
• 📊 Code Complexity Analyzer (loop depth & estimation)

The system is built using a C++ backend (Crow) and a Node.js server, with a responsive web interface.

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🧠 Core Concepts Used

• Stack (Expression Evaluation)
• Parsing & Conversion Algorithms
• Time Complexity Estimation
• REST API Design

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⚙️ Tech Stack

🔹 Backend (Core Logic)

• C++
• Crow Framework
• Custom logic for parsing & evaluation

🔹 Server Layer

• Node.js
• Express.js
• Axios

🔹 Frontend

• EJS
• Bootstrap 5
• Font Awesome

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🏗️ Architecture

Browser (UI)
     ↓
Node.js (Express Server)
     ↓
C++ API (Crow)
     ↓
Data Structure Logic (Stack / Analysis)

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✨ Features

🔹 Expression Evaluator

• Supports:

  • Infix
  • Prefix
  • Postfix

• Converts between formats

• Evaluates final result

🔹 Code Analyzer

• Counts:

  • for loops
  • if / else
  • while loops

• Calculates:

  • Maximum nesting depth
  • Estimated time complexity

🔹 Error Handling

• Structured JSON responses

• Handles:

  • Invalid expressions
  • Empty input
  • Division by zero
  • Invalid code input

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📦 API Endpoints

🔹 POST /expression

Request:

{
  "expression": "5 6 2 * + 3 -"
}

Response:

{
  "result": 14,
  "prefix": "- + 5 * 6 2 3",
  "infix": "((5 + (6 * 2)) - 3)",
  "postfix": "5 6 2 * + 3 -"
}

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🔹 POST /analyze

Request:

{
  "code": "for(int i=0;i<n;i++){...}"
}

Response:

{
  "for": 1,
  "if": 0,
  "while": 0,
  "maxDepth": 1,
  "estimatedComplexity": "O(n)"
}

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🧪 Testing

The API has been tested using:

• Curl
• Browser integration

Test cases include:

• Valid expressions
• Invalid inputs
• Edge cases (empty input, divide by zero)
• Nested loops for complexity

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🚀 Getting Started

🔹 1. Clone the repository

git clone https://github.com/your-username/your-repo.git
cd your-repo

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🔹 2. Setup Node.js

npm install

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🔹 4. Run C++ Server

g++ main.cpp -o app -lpthread
./app

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🔹 5. Run Node Server

node index.js

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🔹 6. Open in browser

http://localhost:3000/home

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📸 Screenshots

🏠 Homepage

🧮 Expression Evaluator

📊 Code Analyzer

⚠️ Error Handling

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📈 Future Improvements

• Live evaluation (no page reload)
• Expression history
• Step-by-step stack visualization
• Support for variables

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👨‍💻 Author

Subhranil Mandal

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📄 License

This project is for educational purposes.

Future Improvements / Roadmap

UI & UX Improvements

• Add hover effects on result cards
• Add smooth animations and transitions
• Improve mobile responsiveness
• Add icons for loops, conditions, complexity, etc.
• Add loading states while analyzing
• Add toast notifications for errors/success
• Add dark/light theme toggle
• Improve typography and spacing consistency

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Visualization Features

Charts & Graphs

• Add bar chart for loop/condition counts
• Add pie chart for code structure distribution
• Add complexity visualization meter
• Add nesting depth tree visualization
• Add execution flow visualization
• Add expression conversion step visualization

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Expression Analyzer Improvements

• Step-by-step infix to postfix conversion
• Stack visualization during conversion
• Expression tree generation
• Expression validation with error highlighting
• Support variables and functions
• Support advanced mathematical operators
• Add expression evaluation support

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Code Analyzer Improvements

• Better time complexity detection
• Space complexity estimation
• Detect recursion
• Detect nested loops more accurately
• Detect switch/case statements
• Detect functions/classes
• Detect unreachable code
• Detect infinite loops
• Add cyclomatic complexity analysis
• Add code smell detection

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Advanced Features

• Syntax highlighting
• Monaco editor integration
• File upload support
• Export analysis report as PDF
• Save analysis history
• Authentication system
• AI-based code suggestions
• Real-time analysis while typing

Multi-language Support

• C++
• Java
• Python
• JavaScript

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Dashboard Ideas

• Analysis statistics dashboard
• Previous analysis history
• Complexity trend graphs
• Most used structures analytics
• User performance analytics

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Dev Tool Inspired Features

• Git visualizer
• Regex engine visualizer
• Debugger simulation
• AST (Abstract Syntax Tree) visualization
• Compiler pipeline visualization
• Memory/stack visualization
• Tokenizer visualization

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Performance Improvements

• Optimize parser speed
• Improve large code handling
• Lazy rendering for large outputs
• Better state management
• Backend optimization

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Long-Term Vision

• Turn project into a complete developer toolkit
• Add interactive learning mode
• Add DSA visualization support
• Add competitive programming utilities
• Add collaborative sharing features
• Add plugin architecture for custom analyzers