solidity学习

变量：

// SPDX-License-Identifier: MIT pragma solidity ^0.8.20; contract HelloWorld{ bool boolVar = true; bool boolVar2 = false; uint256 uintVAR = 256; int256 intVAR = -256; bytes32 bytes8Var = "Hellffffffffffffffffffffffffofff"; string stringVar = "Hello Worldeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"; address addVar = 0x5B38Da6a701c568545dCfcB03FcB875f56beddC4; }

函数

public private Internal External

存储模式：

storage : 永久形存储(合约中的变量默认为storage)

暂时形存储

memory：可以修改

calldata：不可修改

函数、结构体、数组、映射

// SPDX-License-Identifier: MIT pragma solidity ^0.8.20; // struct: 结构体 // array: 数组 // mapping: 映射 contract HelloWorld{ string stringVar = unicode"去你妈的深圳"; // 中文需要前面加 unicode Solidity 默认只支持 ASCII 字符， struct Info{ string phrase; uint id; address addr; } Info[] infos; mapping (uint => Info) infoMapping; function sayHello(uint _id) public view returns (string memory ){ if(infoMapping[_id].addr == address(0x0)){ return addinfo(stringVar); }else { return addinfo(infoMapping[_id].phrase); } // for (uint i =0; i<infos.length; i++){ // if(infos[i].id == _id){ // return addinfo(infos[i].phrase); // } // } // return addinfo(stringVar); } function setHelloWorld(string memory newString, uint _id) public { // uint 为基础数据类型 不用加memory // stringVar = newString; Info memory info = Info(newString,_id,msg.sender); // infos.push(info); infoMapping[_id] = info; } function addinfo(string memory helloWorldStr) internal pure returns (string memory ){ return string.concat(helloWorldStr, "from Frank's contract"); } }

合约工厂操作合约

// SPDX-License-Identifier: MIT pragma solidity ^0.8.20; import { HelloWorld } from "./test.sol"; // 1、直接引入一个文件系统下的合约 // 2、引入github上的合约 // 3、通过包引入第三方的包 contract HelloWorldFactory{ HelloWorld hw; HelloWorld[] hws; function creatHelloWorld() public { hw = new HelloWorld(); hws.push(hw); } function getHelloWorldByIndex(uint _index) public view returns (HelloWorld) { return hws[_index]; } function callSayHelloFromFactory(uint _index, uint _id) public view returns(string memory){ return hws[_index].sayHello(_id); } function callSetHelloWorldFromFactory(uint _index,string memory newString, uint _id)public { hws[_index].setHelloWorld(newString,_id); } }