ERC20代币 #

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract ERC20 {
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public totalSupply;
    
    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;
    
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    
    constructor(
        string memory _name,
        string memory _symbol,
        uint8 _decimals,
        uint256 _totalSupply
    ) {
        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        totalSupply = _totalSupply * 10 ** uint256(_decimals);
        balanceOf[msg.sender] = totalSupply;
        
        emit Transfer(address(0), msg.sender, totalSupply);
    }
    
    function transfer(address to, uint256 amount) public returns (bool) {
        require(to != address(0), "ERC20: transfer to zero address");
        require(balanceOf[msg.sender] >= amount, "ERC20: insufficient balance");
        
        balanceOf[msg.sender] -= amount;
        balanceOf[to] += amount;
        
        emit Transfer(msg.sender, to, amount);
        return true;
    }
    
    function approve(address spender, uint256 amount) public returns (bool) {
        require(spender != address(0), "ERC20: approve to zero address");
        
        allowance[msg.sender][spender] = amount;
        
        emit Approval(msg.sender, spender, amount);
        return true;
    }
    
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public returns (bool) {
        require(from != address(0), "ERC20: transfer from zero address");
        require(to != address(0), "ERC20: transfer to zero address");
        require(balanceOf[from] >= amount, "ERC20: insufficient balance");
        require(allowance[from][msg.sender] >= amount, "ERC20: insufficient allowance");
        
        balanceOf[from] -= amount;
        balanceOf[to] += amount;
        allowance[from][msg.sender] -= amount;
        
        emit Transfer(from, to, amount);
        return true;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract MyToken is ERC20, Ownable {
    uint8 private _decimals;
    
    constructor(
        string memory name,
        string memory symbol,
        uint8 decimals_,
        uint256 initialSupply
    ) ERC20(name, symbol) {
        _decimals = decimals_;
        _mint(msg.sender, initialSupply * 10 ** decimals_);
    }
    
    function decimals() public view virtual override returns (uint8) {
        return _decimals;
    }
    
    function mint(address to, uint256 amount) public onlyOwner {
        _mint(to, amount);
    }
    
    function burn(uint256 amount) public {
        _burn(msg.sender, amount);
    }
}

import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Capped.sol";

contract MintableToken is ERC20, ERC20Burnable, ERC20Capped, Ownable {
    constructor(
        string memory name,
        string memory symbol,
        uint256 cap
    ) ERC20(name, symbol) ERC20Capped(cap) {}
    
    function mint(address to, uint256 amount) public onlyOwner {
        _mint(to, amount);
    }
}

import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Pausable.sol";

contract PausableToken is ERC20, ERC20Pausable, Ownable {
    function pause() public onlyOwner {
        _pause();
    }
    
    function unpause() public onlyOwner {
        _unpause();
    }
}

// 使用uint256而非uint8节省Gas
uint256 private _totalSupply;

// 批量转账
function batchTransfer(
    address[] memory recipients,
    uint256[] memory amounts
) public {
    require(recipients.length == amounts.length, "Length mismatch");
    
    for (uint256 i = 0; i < recipients.length; i++) {
        transfer(recipients[i], amounts[i]);
    }
}