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| // SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface IERC20 {
// 获取合约地址
function getAddress() external view returns (address);
// 获取代币发行总量
function totalSupply() external view returns (uint256);
// 根据地址获取代币的余额
function balanceOf(address account) external view returns (uint256);
// 代理可转移的代币数量
function allowance(address owner, address supender) external view returns (uint256);
// 转账
function transfer(address recipient, uint256 amount) external returns (bool);
// 设置代理能转账的金额
function approve(address owner, address spender, uint256 amount) external returns (bool);
// 转账
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);
}
// 代币实现
contract ERC20Basic is IERC20 {
string public constant name = "X"; // 代币名称
string public constant symbol = "X"; // 代币简称
uint8 public constant decimals = 18;
mapping(address => uint256) balances; // 地址对应的余额数量
mapping(address => mapping(address => uint256)) allowedBalence; // 代理商能处理的代币数量
uint256 totalSupply_ = 10 ether; // 发行数量，ether指的是单位，类似吨，也可以使用8个0
constructor () {
balances[msg.sender] = totalSupply_; // 将代币分发给创建者
}
// 获取合约地址
function getAddress() external override view returns (address){
return address(this); // 当前合约的地址
}
// 获取代币发行总量
function totalSupply() external override view returns (uint256){
return totalSupply_;
}
// 根据地址获取代币的余额
function balanceOf(address tokenOwner) public override view returns (uint256){
return balances[tokenOwner]; // 根据地址获取余额
}
// 转账
function transfer(address receiver, uint256 amount) public override returns (bool){
require(amount <= balances[msg.sender]);
balances[msg.sender] = balances[msg.sender]-amount;
balances[receiver] = balances[receiver]+amount;
emit Transfer(msg.sender, receiver, amount);
return true;
}
// 设置代理能转账的金额
function approve(address owner, address delegate, uint256 amount) external override returns (bool){
allowedBalence[owner][delegate] = amount;
emit Approval(owner, delegate, amount);
return true;
}
// 代理可转移的代币数量
function allowance(address owner, address delegate) external override view returns (uint256){
return allowedBalence[owner][delegate];
}
// 转账
function transferFrom(address owner, address buyer, uint256 amount) external override returns (bool){
require(amount <= balances[owner]);
require(amount <= allowedBalence[owner][msg.sender]);
balances[owner] = balances[owner]-amount;
allowedBalence[owner][buyer] = allowedBalence[owner][buyer]-amount;
balances[buyer] = balances[buyer]+amount;
emit Transfer(owner, buyer, amount);
return true;
}
}
contract Swap {
IERC20 public token;
event Buy(uint256 amount);
event Sell(uint256 amount);
event Withdraw(address _addrss,uint256 _amount);
constructor(){
token = new ERC20Basic();
}
function buy()public payable {
uint256 inAmount = msg.value;
uint256 dexBalance = token.balanceOf(address(this));
require(inAmount > 0,'You need send some ether!');
require(inAmount <= dexBalance,'Not enough tokens in the reserve');
uint256 outAmount = inAmount * 20;
token.transfer(msg.sender,outAmount);
emit Sell(outAmount);
}
function approve(uint256 amount) public returns(bool){
return token.approve(msg.sender,address(this),amount);
}
function sell(uint256 amount) public {
/// 在这里只简单演示卖掉erc20代币，退回合约中的eth
require(amount > 0,'You need to sell at least some tokens');
uint256 allowance = token.allowance(msg.sender,address(this));
require(amount <= allowance,'check the token allowance');
///发送ERC20代币给合约
token.transferFrom(msg.sender,address(this),amount);
uint256 withdrawAmount = address(this).balance;
/// 退回eth
payable(msg.sender).call{value: withdrawAmount}("");
///触发事件
emit Withdraw(address(msg.sender),withdrawAmount);
emit Sell(amount);
}
function getDexBalance() public view returns(uint256){
return token.balanceOf(address(this));
}
function getOwnerBalance() public view returns(uint256){
return token.balanceOf(msg.sender);
}
function getTotalSupply() public view returns(uint256){
return token.totalSupply();
}
function getAllowance() public view returns(uint256){
return token.allowance(msg.sender,address(this));
}
function getEthBalance() public view returns(uint256){
return address(this).balance ;
}
}
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