# 理想区块链-DEX代码

**Published by:** [xin](https://paragraph.com/@xinchain/)
**Published on:** 2022-07-05
**URL:** https://paragraph.com/@xinchain/dex

## Content

// SPDX-License-Identifier: GPL-3.0 pragma solidity 0.8.10; library safeMath { function sub(uint256 a, uint256 b) internal pure returns (uint256) { assert(b <= a); return a - b; } function add(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a + b; assert(c >= a); return c; } } 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 = "ERC-xinChain"; // 代币名称 string public constant symbol = "ERC-xin"; // 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 using safeMath for uint256; constructor () { balances[msg.sender] = totalSupply_; // 将代币分发给创建者 } // 获取合约地址 function getAddress() external view returns (address){ return address(this); // 当前合约的地址 } // 获取代币发行总量 function totalSupply() external 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].sub(amount); balances[receiver] = balances[receiver].add(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 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 view returns (uint256){ return allowedBalence[owner][delegate]; } // 转账 function transferFrom(address owner, address buyer, uint256 amount) external returns (bool){ require(amount <= balances[owner]); require(amount <= allowedBalence[owner][msg.sender]); balances[owner] = balances[owner].sub(amount); allowedBalence[owner][buyer] = allowedBalence[owner][buyer].sub(amount); balances[buyer] = balances[buyer].add(amount); emit Transfer(owner, buyer, amount); return true; } } contract DEX { event Bought(uint256 amount); event Sold(uint256 amount); IERC20 public token; constructor () { token = new ERC20Basic(); } // 买入 function buy() payable public { uint256 amountTobuy = msg.value; //传入以太坊 uint256 dexBalance = token.balanceOf(address(this)); //此合约中自己创建代币的数量 require(amountTobuy > 0 , "You need to send some Ethoer"); // amountTobuy 必须传入以太，使用以太购买此代币 require(amountTobuy <= dexBalance, "Not enough tokens in the reserve"); // 合约中代币的数量要大于要购买的量 token.transfer(msg.sender, amountTobuy); emit Bought(amountTobuy); } function sell(uint256 amount) public { require(amount > 0, "You need to sell at least some tokens."); // 卖出数量要大于0 uint256 allowance = token.allowance(msg.sender, address(this)); require(allowance >= amount, "check the token allowance"); token.transferFrom(msg.sender, address(this), amount); emit Sold(amount); } function getDexBalance() public view returns(uint256) { return token.balanceOf(address(this)); } function getOwnerBalance() public view returns(uint256) { return token.balanceOf(msg.sender); } function getAddress() public view returns (address) { return address(this); } function getTokenAddress() public view returns (address) { return token.getAddress(); } function getTotalSupply() public view returns (uint256) { return token.totalSupply(); } function getSenderAddress() public view returns (address) { return address(msg.sender); } function getAllowance() public view returns (uint256) { uint256 allowance = token.allowance(msg.sender, address(this)); return allowance; } // 授权当前合约转移代币数量 function approve(uint256 amount) public returns(bool) { bool isApprove = token.approve(msg.sender, address(this), amount); return isApprove; } }

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