// SPDX-License-Identifier: GPL-3.0 pragma solidity >=0.7.0 <0.9.0; import "hardhat/console.sol"; //ERC20 同質化代幣，每個代幣的本質或性質都是相同 //ETH 是原生代幣，它不是ERC20代幣,它們兩是不能協同作業，所以需要將ETH轉換成WETH(ERC20) //ERC20 必須實作相應的介面(規范),參見 https://eips.ethereum.org/EIPS/eip-20
//totalSupply 代幣發行總供應量，它即可以固定不變，又可以根據業務需求而改變 //totalSupply 代幣發行總供應量是否可變，取決于合約是否存在mint或burn函式/方法 //balanceOf(owner) 獲取某個賬戶的余額，所有賬戶余額的總和必須等于totalSupply
//approve 授權一定數量的代幣給第三方/交易所/代理人，注意，是授權而不是發送代幣給第三方 //approve 必須包含3個引數，Owner:誰授權代幣給第三方，Spender:第三方/交易所/代理人,Amount:授權數額 //allowance 保存approve方法的3項資料
//transfer 轉賬，接收2個引數，from:msg.sender; to:轉入; amount:金額 //transferFrom 轉賬，接收3個引數，from:轉出; to:轉入; amount:金額 //transfer與transferFrom使用場景不一樣，transfer用在本合約轉賬，transferFrom用在第三方/去中心交易所/代理人 //event Approval與Transfer 將交易等日志資訊寫入區塊鏈，非常重要
//V1 interface IERC20V1 { event Approval(address indexed owner ,address indexed spender ,uint256 amount); event Transfer(address indexed from ,address indexed to ,uint256 amount);
function name() external pure returns (string memory); function symbol() external pure returns (string memory); function decimals() external pure returns (uint8); //對應狀態變數totalSupply 代幣發行總供應量 function totalSupply() external view returns(uint256); //balanceOf(owner) 獲取某個賬戶的余額 function balanceOf(address owner) external view returns(uint256); //approve 授權一定數量的代幣給第三方/交易所/代理人 function approve(address spender, uint amount) external returns (bool); //allowance 保存approve方法的3項資料 function allowance(address owner, address spender) external view returns (uint256); function transfer(address to, uint amount) external returns(bool);
function transferFrom(address from, address to,uint amount) external returns(bool);
}
contract ERC20V1 is IERC20V1 {
string public constant name = "XingZheChain"; string public constant symbol = "XZC"; uint8 public constant decimals = 18; //totalSupply 代幣發行總供應量 uint256 public totalSupply; mapping(address => uint256) public balanceOf; address public _owner;
mapping(address => mapping(address => uint256)) public allowance;
constructor(uint256 _initTotalSupply){ _owner = msg.sender; //預挖給創建者代幣 mint(msg.sender,_initTotalSupply); }
modifier onlyOwner() { require(_owner == msg.sender,"Ownable:caller is not the owner"); _; } //挖掘出新代幣以及挖給那個地址 //合約創建者呼叫 function mint(address to ,uint256 amount) public onlyOwner { totalSupply = totalSupply += amount; balanceOf[to] = balanceOf[to] += amount; } //燃燒自己的代幣 function burn(uint256 amount) public { address from = msg.sender; balanceOf[from] = balanceOf[from] -= amount; totalSupply = totalSupply -= amount; }
function _approve(address owner, address spender, uint amount) private { allowance[owner][spender] = amount; emit Approval(owner ,spender ,amount); }
function approve(address spender, uint amount) external returns(bool) { _approve(msg.sender, spender, amount); return true; }
function _transfer(address from, address to,uint amount) private { balanceOf[from] = balanceOf[from] -= amount; balanceOf[to] = balanceOf[to] += amount; emit Transfer(from ,to ,amount); }
function transfer(address to, uint amount) external returns(bool){ _transfer(msg.sender, to, amount); return true; }
function transferFrom(address from, address to,uint amount) external returns(bool){ uint256 currentAllowance = allowance[from][msg.sender]; require(currentAllowance >= amount,"ERC20: insufficient allowance"); allowance[from][msg.sender] = currentAllowance -= amount; //console.log("msg.sender ->",address(msg.sender)); _transfer(from ,to ,amount); return true; } }
//建議去中心化交易所 contract Dex { address public erc20V1;
constructor(address _erc20V1){ erc20V1 = _erc20V1; }
function transferFromTo(address to ,uint amount) external { IERC20V1(erc20V1).transferFrom(msg.sender ,to ,amount); }
function transferTo(address to,uint amount) external { IERC20V1(erc20V1).transfer(to,amount); } }
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標籤：區塊鏈
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