52_怀达_第六次作业_1

Lesson-3/README.md

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+## 硅谷live以太坊智能合约频道官方地址
+
+### 第三课《智能合约后端优化和产品化》
+
+目录结构
+  <br/>|
+  <br/>|--orgin 课程初始代码
+  <br/>|
+  <br/>|--assignment 课程作业提交代码
+<br/> 
+### 本节知识点
+第3课：智能合约后端优化和产品化
+- 如何通过数据结构优化降低合约执行成本
+- 合约的继承
+- 巧用modifier
+- 以太坊函数库的使用和基本介绍

Lesson-3/assignment/C3 Linearization.sol

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+contract O
+contract A is O
+contract B is O
+contract C is O
+contract K1 is A, B
+contract K2 is A, C
+contract Z is K1, K2
+
+https://en.wikipedia.org/wiki/C3_linearization
+https://blog.tedxiong.com/C3_Linearization.html
+
+solidity的继承链是靠右的更近，这点和python不一样
+
+L[O] = [O]
+L[A] = [A,O]
+L[B] = [B,O]
+L[C] = [C,O]
+L[k1] = [K1]+merge(L[B],L[A],[B,A])  // merge规则：按照继承顺序加入merge，最后再加一个所有父类顺序添加的序列
+      = [K1]+merge([B,O],[A,O],[B,A]) // 规则：取一个元素（它是其他序列中的第一个元素，或不在其他序列出现,如果有多个元素符合，选前面一个）加到最前序列后面
+      = [K1,B]+merge([O],[A,O],[A])
+      = [K1,B,A,O]
+L[K2] = [k2,C,A,O]
+L[Z]  = [Z] + merge(L[K2],L[K1],[K2,K1])
+      = [Z] + merge([K2,C,A,O],[k1,B,A,O],[K2,K1])
+      = [Z,K2,C,K1,B,A,O]

Lesson-3/assignment/README.md

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+## 硅谷live以太坊智能合约 第三课作业
+这里是同学提交作业的目录
+
+### 第三课：课后作业
+- 第一题：完成今天所开发的合约产品化内容，使用Remix调用每一个函数，提交函数调用截图
+- 第二题：增加 changePaymentAddress 函数，更改员工的薪水支付地址，思考一下能否使用modifier整合某个功能
+- 第三题（加分题）：自学C3 Linearization, 求以下 contract Z 的继承线
+- contract O
+- contract A is O
+- contract B is O
+- contract C is O
+- contract K1 is A, B
+- contract K2 is A, C
+- contract Z is K1, K2

Lesson-3/assignment/payroll.sol

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+pragma solidity ^0.4.14;
+import './SafeMath.sol';
+import './Ownable.sol';
+
+contract Payroll is Ownable{
+
+    using SafeMath for uint;
+
+    struct Employee{
+        address employeeAddress;
+        uint salary;
+        uint lastPayday;
+    }
+   mapping(address => Employee) public employeeMapping;
+   uint constant payDuration = 30 seconds;
+   address ownerAddress;
+   uint totalSalary = 0;
+
+
+   modifier employeeExist(address addr){
+       var employee = employeeMapping[addr];
+       require(employee.employeeAddress != 0x0);
+       _;
+   }
+
+   function _partialPay(Employee emp) private{
+       uint totalSalary = emp.salary.mul(now.sub(emp.lastPayday)).div(payDuration);
+
+       emp.employeeAddress.transfer(totalSalary);
+   }
+
+   function addEmployee(address addr,uint sal) onlyOwner {
+
+       uint oneSalary = sal.mul(1 ether);
+       totalSalary = totalSalary.add(oneSalary);
+       employeeMapping[addr] = Employee(addr,oneSalary,now);
+   }
+   function removeEmployee(address addr) onlyOwner employeeExist(addr){
+       var employee = employeeMapping[addr];
+       totalSalary = totalSalary.sub(employee.salary);
+       _partialPay(employee);
+       delete(employeeMapping[addr]);
+
+   }
+   function updateEmployee(address oldAddress,address newAddresss,uint sal) onlyOwner employeeExist(oldAddress){
+
+        var employee = employeeMapping[oldAddress];
+        uint oneSalary = sal.mul(1 ether);
+        totalSalary = totalSalary.sub(employee.salary).add(oneSalary);
+        employee.employeeAddress = newAddresss;
+        employee.salary = oneSalary;
+
+   }
+   function changePaymentAddress(address oldAddress,address newAddresss) onlyOwner employeeExist(oldAddress){
+       var employee = employeeMapping[oldAddress];
+       employee.employeeAddress = newAddresss;
+   }
+
+
+   function calculateRunway() view returns(uint){
+
+       uint selfbalance = getAddressBalance(this);
+       return selfbalance.div(totalSalary);
+   }
+    function hasEnoughFund() returns(bool){
+       return calculateRunway() > 0;
+   }
+
+   function addFund() payable  returns(uint){
+
+       return this.balance;
+   }
+
+
+   function getPaid() employeeExist(msg.sender) {
+       var employee = employeeMapping[msg.sender];
+       uint intervalTime = now.sub(employee.lastPayday);
+       require(intervalTime >= payDuration);
+
+       uint times = intervalTime.div(payDuration);
+       employee.lastPayday = employee.lastPayday.add(times.mul(payDuration));
+       employee.employeeAddress.transfer(employee.salary.mul(times));
+   }
+
+   function getAddressBalance(address addr) public view returns(uint){
+       return addr.balance;
+   }
+
+}

Lesson-3/orgin/README.md

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+## 硅谷live以太坊智能合约 第三课
+
+这里是每一课的初始代码，有需要的同学可以参考

Lesson-4/README.md

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+## 硅谷live以太坊智能合约频道官方地址
+
+### 第四课《使用Truffle架构进行前后端交互，测试，部署》
+
+目录结构
+  <br/>|
+  <br/>|--orgin 课程初始代码
+  <br/>|
+  <br/>|--assignment 课程作业提交代码
+<br/> 
+### 本节知识点
+第4课：使用Truffle架构进行前后端交互，测试，部署
+- 为什么要用Truffle，Truffle的基本概念
+- Truffle 的command line 功能
+- 初始化项目与Truffle项目目录结构
+- 编译部署合约到testrpc