Solidity Voting Contract

A decentralized voting system built with Solidity and Foundry, allowing users to vote on candidates within a specified time period.

Features

• Time-Bound Voting: Voting is only allowed within a defined start and end time
• Single Vote Per Address: Each address can vote only once to prevent double voting
• Candidate Management: Add multiple candidates before voting begins
• Vote Counting: Real-time vote tallying for each candidate
• Secure: Built with Solidity best practices and comprehensive testing

Contract Overview

The Voting contract includes the following functionality:

• constructor(uint256 _start, uint256 _end): Initialize voting with start and end timestamps
• addCandidate(string memory _name): Add a candidate to the election
• vote(uint256 _index): Cast a vote for a candidate by index
• candidates(uint256): View candidate information (name and vote count)
• hasVoted(address): Check if an address has already voted

Prerequisites

• Foundry installed
• Solidity ^0.8.20

Installation

1. Clone the repository:

git clone <repository-url>
cd solidity-voting-contract

2. Install dependencies:

forge install

Usage

Build the Contract

forge build

Run Tests

forge test

Run specific test:

forge test --match-test testVoteOnce

Deploy the Contract

1. Set up your environment variables:

export PRIVATE_KEY=your_private_key
export RPC_URL=your_rpc_url

2. Deploy using the script:

forge script script/Deploy.sol --rpc-url $RPC_URL --private-key $PRIVATE_KEY --broadcast

Interact with Deployed Contract

Use Cast to interact with the deployed contract:

# Add a candidate
cast send <contract_address> "addCandidate(string)" "Candidate Name" --rpc-url $RPC_URL --private-key $PRIVATE_KEY

# Vote for candidate (index 0)
cast send <contract_address> "vote(uint256)" 0 --rpc-url $RPC_URL --private-key $PRIVATE_KEY

# Check vote count
cast call <contract_address> "candidates(uint256)" 0 --rpc-url $RPC_URL

Testing

The project includes comprehensive tests covering:

• Single vote enforcement
• Vote count incrementing
• Voting period validation
• Double voting prevention

Run tests with verbose output:

forge test -v

Project Structure

├── src/
│   └── Voting.sol          # Main voting contract
├── test/
│   └── Voting.t.sol        # Contract tests
├── script/
│   └── Deploy.sol          # Deployment script
├── foundry.toml            # Foundry configuration
└── README.md               # This file

Security Considerations

• Voting is time-bound to prevent indefinite voting periods
• One vote per address prevents manipulation
• Input validation for candidate indices
• Uses Solidity ^0.8.20 for enhanced security features

Contributing

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Ensure all tests pass
5. Submit a pull request

License

This project is licensed under the MIT License.