## 基于Remix以太坊开发例程及个人感悟 创作来源:
创作来源:
B站视频: Up主:夏夜書.
优快云文章: 基于Remix-Ethereum开发的app打分智能合约(代码调试即测试文档编写详解).
开发环境: Remix.
本文面向刚刚接触以太坊区块链编程,希望能够在自我学习过程中巩固知识,如果有什么问题欢迎各位提出建议。
一、通过实际操作中对以太坊智能合约编程有个初步认识
首先,应该观看上文引用的夏夜书up主的视频。该视频首先介绍了新旧Remix编程差异,其次用一个例程从零到实现的过程教会我们来开发一个简单的程序。
具体实现代码如下:
pragma solidity >=0.4.22 <0.7.0;
/**
* @title Billboard
* @dev Billboard
*/
contract Billboard {
struct App {
string name;
address owner;
uint8[] stars;
mapping(address => uint) star0f;
uint totalStar;
}
App[] public apps;
// event for EVM logging
event Publish(string indexed name, address indexed owner, uint appId);
event Star(address indexed user, uint indexed appId, uint8 num);
/**
* @dev publish
*
*/
function publish(string memory name) public {
require(bytes(name).length>0, "name empty error");
apps.push(App(name,msg.sender,new uint8[](0),0));
emit Publish(name,msg.sender,apps.length-1);
}
/**
* @dev star
* 10,5 4,4 5,3 6,2 2,1
*/
function star(uint appId, uint8 num) public {
require(appId < apps.length,"app id error");
require(num <= 5 && num >= 1, "star num error");
require(apps[appId].star0f[msg.sender] == 0,"user error");
App storage app = apps[appId];
app.stars.push(num);
app.totalStar += num;
app.star0f[msg.sender] = app.stars.length-1;
emit Star(msg.sender,appId,num);
}
/**
* @dev Return value
* @return value of 'number'
*/
function top() public view returns (uint[] memory topIds){
topIds = new uint[](10);
for(uint appId = 1; appId < apps.length ; appId++){
uint topLast = appId < topIds.length? appId:topIds.length-1;
if(appId >= topIds.length&&apps[appId].totalStar <= apps[topIds[topLast]