IERC20

IERC20 是 ERC20 标准的接口规范,它定义和规范了一个标准 ERC20 代币合约应该实现的功能。这里让 ERC20 合约直接继承自 IERC20 接口。

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;interface IERC20 { // 当 `value` 单位的货币从账户 (`from`) 转账到另一账户 (`to`)时 触发event Transfer(address indexed from, address indexed to, uint256 value);// 当 `value` 单位的货币从账户 (`owner`) 授权给另一账户 (`spender`)时触发 event Approval(address indexed owner, address indexed spender, uint256 value);// 返回代币总供给.function totalSupply() external view returns (uint256);// 返回账户`account`所持有的代币数.function balanceOf(address account) external view returns (uint256);// 转账 `amount` 单位代币，从调用者账户到另一账户 `to`.function transfer(address to, uint256 amount) external returns (bool);// 返回`owner`账户授权给`spender`账户的额度，默认为0。function allowances(address owner, address spender) external view returns (uint256);// 调用者账户给`spender`账户授权 `amount`数量代币。    function approve(address spender, uint256 amount) external returns (bool);// 通过授权机制，从`from`账户向`to`账户转账`amount`数量代币。转账的部分会从调用者的`allowances`中扣除。function transferFrom( address from, address to, uint256 amount ) external returns (bool);
}

ERC20

ERC20 是以太坊上最常见和最流行的代币标准之一, 它定义了一套规则和接口,使得不同的代币可以在同一个平台上互相交换和使用，是实现同质化代币的常见选择。ERC20 实现了账户余额、转账、授权、授权转账以及总供给量的代币转账功能。

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;import "./IERC20.sol"; contract MyToken is IERC20 {mapping(address => uint256) public override balanceOf;mapping(address => mapping(address => uint256)) public override allowances;uint256 public totalSupply;     // 代币总供给string public name;             // 代币名称string public symbol;           // 代币代号uint8 public decimals = 18;     // 小数位数// 构造函数 constructor(string memory name_, string memory symbol_) {name = name_;symbol = symbol_;}// 转账function transfer(address recipient, uint256 amount) public override returns (bool) {_transfer(msg.sender, recipient, amount);return true;}// 授权转账 function transferFrom(address sender, address recipient, uint amount) external override returns (bool){_transfer(sender, recipient, amount); uint256 currentAllowance = allowances[sender][msg.sender]; require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowances");           // 是否超过授权额度 _approve(sender, msg.sender, currentAllowance - amount);return true;}   function _transfer(address sender, address recipient, uint256 amount) internal {require(sender != address(0), "ERC20: transfer from the zero address");require(recipient != address(0), "ERC20: transfer to the zero address");uint256 senderBalance = balanceOf[sender];require(senderBalance >= amount,  "ERC20: transfer amount exceeds balance");balanceOf[sender] = senderBalance - amount;balanceOf[recipient] += amount;emit Transfer(sender, recipient, amount);}// 授权 function approve(address spender, uint amount) external override returns (bool){_approve(msg.sender, spender, amount); return true;}function _approve(address owner, address spender, uint256 amount) internal {require(owner != address(0), "ERC20: approve from the zero address");   // 授权无效地址 require(spender != address(0), "ERC20: approve to the zero address");allowances[owner][spender] = amount;emit Approval(owner, spender, amount);}// 锻造代币function mint(address account, uint amount) external {require(account != address(0), "ERC20: mint to the zero address");balanceOf[account] += amount; totalSupply += amount;emit Transfer(address(0), msg.sender, amount);}// 销毁代币 function burn(address account, uint amount) external {require(account != address(0), "ERC20: burn from the zero address");uint256 accountBalance = balanceOf[account]; require(accountBalance >= amount, "ERC20: burn amount exceeds balance");balanceOf[account] = accountBalance - amount;totalSupply -= amount; emit Transfer(account, address(0), amount); }
}

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