交易所区块链开发

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

interface IERC20 {
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function approve(address spender, uint256 amount) external returns (bool);
    function balanceOf(address account) external view returns (uint256);
}

contract SimpleDEX {
    address public tokenA;
    address public tokenB;
    uint256 public exchangeRate; // tokenA to tokenB

    constructor(address _tokenA, address _tokenB, uint256 _exchangeRate) {
        tokenA = _tokenA;
        tokenB = _tokenB;
        exchangeRate = _exchangeRate;
    }

    function swapTokens(uint256 amountA) external {
        IERC20(tokenA).transferFrom(msg.sender, address(this), amountA);
        uint256 amountB = amountA * exchangeRate;
        IERC20(tokenB).transfer(msg.sender, amountB);
    }
}