🗳️ Synchronized Voting System (C/Linux)

This C program implements a voting system that demonstrates the classic Readers-Writers synchronization problem using POSIX threads, semaphores, and shared memory on Linux.

Developed as part of the Operating Systems course in the Software Engineering program at FAST NUCES, Karachi.

🚀 Features

• ✅ Multiple candidates (up to 10)
• ✅ Supports up to 1000 voters
• ✅ Advanced synchronization using named semaphores
• ✅ Concurrent reading and writing with proper coordination
• ✅ Reader-preference synchronization pattern
• ✅ Comprehensive logging system with timestamps
• ✅ Performance tracking and comparison between modes
• ✅ Prevention of duplicate voting
• ✅ Three operation modes: Manual, Thread, and Process

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🧠 Core Concepts Used

• POSIX Threads (pthread)
• Named Semaphores (sem_open, sem_wait, sem_post)
• Shared Memory (shm_open, mmap)
• Process Management (fork, waitpid)
• Readers-Writers Synchronization
• Signal Handling (SIGINT)
• File I/O and Performance Tracking

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🔧 Synchronization Approach

• 🧑‍🏫 Reader-preference implementation:
  • Multiple observers (readers) can view results simultaneously
  • Voters (writers) get exclusive access
• 🔒 Uses four semaphores:
  • mutex: Protects access to reader count
  • wrt: Controls write access to voting data
  • read_count_sem: Manages reader count access
  • console_sem: Prevents interleaved console output

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📂 System Components

Resource Management

• initialize_resources(): Sets up semaphores and shared memory
• cleanup_resources(): Releases all system resources

Synchronization

• reader_enter(), reader_exit(): Controls observation access
• writer_enter(), writer_exit(): Controls vote casting access

Core Functionality

• cast_vote(): Records votes with proper synchronization
• view_results(): Displays current vote tallies safely

Operational Modes

• manual_mode(): Interactive CLI for voting
• thread_mode(): Simulates voting using threads
• process_mode(): Simulates voting using separate processes

Performance Analysis

• print_performance_comparison(): Analyzes thread vs process efficiency

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🧪 Simulation Modes

1. Manual Mode

   • Interactive CLI interface
   • User manually enters voter and candidate IDs
   • View live results at any time

2. Thread-Based Simulation

   • Creates multiple threads for voters and observers
   • Automatically simulates concurrent voting
   • Measures and logs performance metrics

3. Process-Based Simulation

   • Uses fork() to create child processes for voters and observers
   • Demonstrates IPC via shared memory
   • Allows performance comparison with thread mode

4. Performance Comparison

   • Analyzes efficiency differences between thread and process modes
   • Generates detailed performance reports

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📊 Logging System

• Creates timestamped log files for each session
• Records all voting activities with timestamps
• Maintains separate performance tracking for comparison
• Generates detailed performance analysis reports

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⚙️ Build & Run

🔨 Build

make 

🧹 Clean Up

make clean       # Removes executable and main log
make clear_logs  # Removes all vote log files

▶️ Run

./voting_system