💰 Smart Donation Contract

A simple, secure Ethereum smart contract that allows anyone to donate ETH while only the contract owner can withdraw the funds.

📋 Overview

This Solidity smart contract provides a transparent donation platform where:

• Anyone can donate ETH to the contract

• All donations are tracked and logged

• Only the contract owner can withdraw funds

• Full transparency with public balance checking

✨ Features

• Public Donations: Anyone can donate any amount of ETH

• Donation Tracking: Track individual donations per address

• Owner-Only Withdrawals: Secure withdrawal mechanism for the contract owner

• Event Logging: All donations and withdrawals are logged on the blockchain

• Transparent Balance: Anyone can check the current contract balance

🔧 Contract Functions

donate()

• Visibility: External, Payable

• Description: Allows anyone to donate ETH to the contract

• Requirements: Donation amount must be greater than 0

• Events: Emits Donated event

withdraw()

• Visibility: External

• Description: Allows the owner to withdraw all funds from the contract

• Requirements:

  • Only the owner can call this function

  • Contract must have a balance greater than 0

• Events: Emits Withdrawn event

getBalance()

• Visibility: External, View

• Description: Returns the current balance of the contract

• Returns: Current contract balance in Wei

📊 State Variables

• owner: Address of the contract deployer/owner

• donations: Mapping of donor addresses to their total donated amounts

• totalDonations: Total amount of all donations received

🚀 Deployment

Prerequisites

• Solidity compiler version ^0.8.0

• Ethereum wallet (MetaMask, etc.)

• ETH for gas fees

Deploy Steps

1. Using Remix IDE (Recommended for beginners):

   • Go to Remix Ethereum IDE

   • Create a new file and paste the contract code

   • Compile with Solidity 0.8.0 or higher

   • Deploy to your preferred network (Testnet recommended for testing)

2. Using Hardhat:

   npx hardhat compile
   npx hardhat run scripts/deploy.js --network <network-name>

3. Using Truffle:

   truffle compile
   truffle migrate --network <network-name>

💡 Usage Examples

Donating ETH

// Using Web3.js
await donationContract.methods.donate().send({
    from: userAddress,
    value: web3.utils.toWei('1', 'ether')
});

Checking Balance

// Using Web3.js
const balance = await donationContract.methods.getBalance().call();
console.log('Contract balance:', web3.utils.fromWei(balance, 'ether'), 'ETH');

Withdrawing Funds (Owner Only)

// Using Web3.js
await donationContract.methods.withdraw().send({
    from: ownerAddress
});

🔒 Security Features

• Owner-Only Withdrawal: Only the deployer can withdraw funds

• Secure Transfer Method: Uses call() for ETH transfers (best practice)

• Input Validation: Ensures donations are greater than 0

• Event Logging: All transactions are logged for transparency

📝 Events

Donated(address indexed donor, uint256 amount)

Emitted when a donation is made.

Withdrawn(address indexed owner, uint256 amount)

Emitted when the owner withdraws funds.

⚠️ Important Notes

• The contract deployer becomes the owner automatically

• There is no function to change ownership (intentional for simplicity)

• Always test on a testnet (Goerli, Sepolia) before mainnet deployment

• Ensure you have the private key for the owner address securely stored

🧪 Testing

Consider testing:

1. Donations from multiple addresses

2. Owner withdrawal functionality

3. Non-owner withdrawal attempts (should fail)

4. Zero-value donation attempts (should fail)

5. Balance checking after various operations