Deliverable 1

Web3.js is a JavaScript library that provides an interface for interacting with the Ethereum blockchain. It enables developers to build applications that can interact with smart contracts, query blockchain data, and send transactions.

1. Go to the Remix online IDE.

2. Write a Smart Contract

// SPDX-License-Identifier: MIT
pragma solidity >=0.7.0 <0.9.0;

contract CoinFlip {
    address public sender;
    address public player1;
    address public player2;
    uint256 public balance;

    constructor(address _player1, address _player2) {
        sender = msg.sender;
        player1 = _player1;
        player2 = _player2;
        balance = 0;
    }

    function addEther() external payable {
        require(msg.sender == sender, "Only the sender can add ether.");
        balance += msg.value;
    }

    function distribute() external {
        require(msg.sender == sender, "Only the sender can distribute.");

        uint256 lastDigit = block.timestamp % 10;

        if (lastDigit % 2 == 0) {
            payable(player1).transfer(balance);
        } else {
            payable(player2).transfer(balance);
        }

        balance = 0;
    }
}

        

Create a Solidity file. The extension used for solidity language in which our smart contract is being written is ".sol"

3. Compile the contract

4. Deploy the contract

Head to the Deploy and run transactions section. For our coin flip contract, we have 2 players and a sender. When deploying the contract, we must select an address for the Sender, and the addresses for players 1 and 2. The provided accounts are just test ids and are only meant for testing purposes. Click on transact to deploy the contract in the test environment!

5. Test the contract.

To test this contract we will need to send test Ether from the Senders account to the balance of the smart contract. To do this, I have selected 4 Ethers and clicked the "addEther" function to add this balance (see Fig 4). When I click on the "balance", I see 4 ETH as the current balance. Next, the "distributeEther" function will randomly select either a 0 or a 1 and distribute the balance to either player 1 or 2, based on which play wins. The last figure shows how the sender balance has been reduced and 4 ETH added to Player 1s account.

We have successfully tested a smart contract by following these steps.