第三次作业

Lesson2/README.md

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+## 硅谷live以太坊智能合约频道官方地址
+
+### 第二课《智能合约设计进阶-多员工薪酬系统》
+
+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2课：智能合约设计进阶-多员工薪酬系统
+- 动态静态数组的不同
+- 函数输入参数检查 revert
+- 循环与遍历的安全性
+- 程序运行错误检查和容错：assert与require

Lesson2/assignment/README.md

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+## 硅谷live以太坊智能合约 第二课作业
+这里是同学提交作业的目录
+
+### 第二课：课后作业
+完成今天的智能合约添加100ETH到合约中
+- 加入十个员工，每个员工的薪水都是1ETH
+每次加入一个员工后调用calculateRunway这个函数，并且记录消耗的gas是多少？Gas变化么？如果有 为什么？
+- 如何优化calculateRunway这个函数来减少gas的消耗？
+提交：智能合约代码，gas变化的记录，calculateRunway函数的优化
+

Lesson2/assignment/yours.sol

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+/*作业请提交在这个目录下*/

Lesson2/orgin/README.md

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+## 硅谷live以太坊智能合约 第二课《智能合约设计进阶-多员工薪酬系统》
+
+这里是每一课的初始代码，有需要的同学可以参考

Lesson2/orgin/payroll.sol

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+pragma solidity ^0.4.14;
+
+contract Payroll {
+    struct Employee {
+        address id;
+        uint salary;
+        uint lastPayday;
+    }
+
+    uint constant payDuration = 10 seconds;
+
+    address owner;
+    Employee[] employees;
+
+    function Payroll() {
+        owner = msg.sender;
+    }
+
+    function _partialPaid(Employee employee) private {
+    }
+
+    function _findEmployee(address employeeId) private returns (Employee, uint) {
+    }
+
+    function addEmployee(address employeeId, uint salary) {
+    }
+
+    function removeEmployee(address employeeId) {
+    }
+
+    function updateEmployee(address employeeId, uint salary) {
+    }
+
+    function addFund() payable returns (uint) {
+    }
+
+    function calculateRunway() returns (uint) {
+        uint totalSalary = 0;
+       for (uint i = 0; i < employees.length; i++) {
+            totalSalary += employees[i].salary;
+        }
+        return this.balance / totalSalary;
+    }
+
+    function hasEnoughFund() returns (bool) {
+    }
+
+    function getPaid() {
+    }
+}

Lesson3/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

Lesson3/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

Lesson3/assignment/yours.sol

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+/*作业请提交在这个目录下*/
+pragma solidity ^0.4.14;
+
+contract Payroll {
+    struct Employee {
+        address id;
+        uint salary;
+        uint lastPayday;
+    }
+
+    uint constant payDuration = 10 seconds;
+    uint totalSalary = 0;
+
+    address owner;
+    mapping (address => Employee) private employees;
+
+    modifier onlyOwner() {
+        require(owner == msg.sender);
+        _;
+    }
+
+    modifier onlySelf(address employeeId) {
+        require(employeeId == msg.sender);
+        _;
+    }
+
+    function Payroll() public{
+        owner = msg.sender;
+    }
+
+    function _partialPaid(Employee employee) private {
+      uint amount = (now - employee.lastPayday) / payDuration * employee.salary;
+      employee.id.transfer(amount);
+    }
+
+    function addEmployee(address employeeId, uint salary) public onlyOwner {
+      var employee = employees[employeeId];
+      assert(employee.id == 0x0);
+      employees[employeeId] = Employee(employeeId, salary, now);
+      totalSalary += salary * 1 ether;
+    }
+
+    function removeEmployee(address employeeId) public onlyOwner {
+      var employee = employees[employeeId];
+      assert(employee.id != 0x0);
+      _partialPaid(employees[employeeId]);
+      delete employees[employeeId];
+      totalSalary -= employees[employeeId].salary * 1 ether;
+    }
+
+    function updateEmployee(address employeeId, uint salary) public onlyOwner {
+      var employee = employees[employeeId];
+      assert(employee.id != 0x0);
+      _partialPaid(employee);
+      totalSalary -= employees[employeeId].salary;
+      employees[employeeId].salary = salary * 1 ether;
+      employees[employeeId].lastPayday = now;
+      totalSalary += salary * 1 ether;
+    }
+
+    function addFund() payable public returns (uint) {
+      return this.balance;
+    }
+
+    function calculateRunway() public view returns (uint) {
+        assert(totalSalary > 0);
+        return this.balance / totalSalary;
+    }
+
+    function hasEnoughFund() public view returns (bool) {
+      return calculateRunway() > 0;
+    }
+
+    function checkEmployee(address employeeId) public view returns (uint salary, uint lastPayday) {
+        var employee = employees[employeeId];
+        salary = employee.salary;
+        lastPayday = lastPayday;
+    }
+
+    function getPaid() public {
+      var employee = employees[msg.sender];
+      assert(employee.id != 0x0);
+      uint nextPayday = employees[msg.sender].lastPayday + payDuration;
+      assert(nextPayday < now);
+      employees[msg.sender].lastPayday = nextPayday;
+      employee.id.transfer(employees[msg.sender].salary);
+    }
+
+    function changePaymentAddress(address EmployeeId, address newAddress) public onlySelf(EmployeeId){
+      var employee = employees[msg.sender];
+      assert(employee.id != 0x0);
+      employees[msg.sender].id = newAddress;
+    }
+}

Lesson3/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

Lesson4/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