ERC-20 Token Creation

HOW TO CREATE ERC20 TOKEN ON ETHEREUM BLOCKCHAIN

Get MetaMask Wallet

  • Install MetaMask extension
  • Setup MetaMask account
  • Follow instructions given to you

    Make sure to keep Private Keys and Passphrase safe!

Reference: https://www.youtube.com/watch?v=RUjOeVk-Sz0

Fund Test Network Ether Account

  • Select a network
    • By default: Ethereum Mainnet
    • For testing: Use Ropsten Test Network
  • Copy testnet account address from MetaMask
  • Get test Ether on Ropsten Ethereum Faucet
  • Paste testnet account address from MetaMask
  • Hit ‘Send me test Ether’

Code ERC20 Token

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pragma solidity ^0.5.0;

// ----------------------------------------------------------------------------
// ERC Token Standard #20 Interface
//
// ----------------------------------------------------------------------------
contract ERC20Interface {
    function totalSupply() public view returns (uint);
    function balanceOf(address tokenOwner) public view returns (uint balance);
    function allowance(address tokenOwner, address spender) public view returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

// ----------------------------------------------------------------------------
// Safe Math Library
// ----------------------------------------------------------------------------
contract SafeMath {
    function safeAdd(uint a, uint b) public pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function safeSub(uint a, uint b) public pure returns (uint c) {
        require(b <= a); c = a - b; } function safeMul(uint a, uint b) public pure returns (uint c) { c = a * b; require(a == 0 || c / a == b); } function safeDiv(uint a, uint b) public pure returns (uint c) { require(b > 0);
        c = a / b;
    }
}


contract CodeWithJoe is ERC20Interface, SafeMath {
    string public name;
    string public symbol;
    uint8 public decimals; // 18 decimals is the strongly suggested default, avoid changing it

    uint256 public _totalSupply;

    mapping(address => uint) balances;
    mapping(address => mapping(address => uint)) allowed;

    /**
     * Constrctor function
     *
     * Initializes contract with initial supply tokens to the creator of the contract
     */
    constructor() public {
        name = "CodeWithJoe";
        symbol = "CWJ";
        decimals = 18;
        _totalSupply = 100000000000000000000000000;

        balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }

    function totalSupply() public view returns (uint) {
        return _totalSupply  - balances[address(0)];
    }

    function balanceOf(address tokenOwner) public view returns (uint balance) {
        return balances[tokenOwner];
    }

    function allowance(address tokenOwner, address spender) public view returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }

    function approve(address spender, uint tokens) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        return true;
    }

    function transfer(address to, uint tokens) public returns (bool success) {
        balances[msg.sender] = safeSub(balances[msg.sender], tokens);
        balances[to] = safeAdd(balances[to], tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }

    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
        balances[from] = safeSub(balances[from], tokens);
        allowed[from][msg.sender] = safeSub(allowed[from][msg.sender], tokens);
        balances[to] = safeAdd(balances[to], tokens);
        emit Transfer(from, to, tokens);
        return true;
    }
}

  • Make code adjustments

    • Change contract name ‘CodeWithJoe’
    • Set name of token ‘CodeWithJoe’
    • Set symbol of token ‘CWJ’
    • Set decimals of token ‘18’
    • Set _totalSupply of token ‘100000000000000000000000000’

  • Compile the file name

    • Make sure the compiler version matches
    • Make sure MetaMask account is connected to remix

Deploy Token

  • Deploy contract to Ropsten Test Network
    • Confirm the transaction in MetaMask
  • Click on created transaction link
  • Click on contract
  • Contract should now be live on the Ethereum Test Network
  • Check Token Name / Tracker
  • Check Contract Creator

Verify the smart contract

  • Verify the Smart Contract
    • Enter the contract address you would like to verify
    • Select the Compiler Type ‘Solidity (Single file)’
    • Select the Compiler Version
    • Select the Open Source License Type
    • Click ‘Continue’
  • Paste Solidity Contract Code below
    • Click ‘Verify and Publish’
  • Contract should now be verified on the Ethereum Blockchain

Reference: https://www.youtube.com/watch?v=GDq7r1n9zIU