54_于宏学_第二课作业

Lesson-1/assignment/54_于宏学_第一课作业.sol

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+/*作业请提交在这个目录下*/
+pragma solidity ^0.4.14;
+
+contract Payroll{
+
+    uint constant payDuration  = 2 seconds;
+    address owner;
+    uint salary;
+    address employee;
+    uint lastPayday;
+
+    function Payroll(){
+        owner = msg.sender;
+    }
+
+    function updateEmployee(address e,uint s){
+
+        if (employee != 0x0)
+        {
+            uint payment = salary * (now - lastPayday)/payDuration;
+            employee.transfer(payment);
+        }
+
+        employee = e;
+        salary = s * 1 ether;
+        lastPayday = now;
+    }
+
+    function addFund() payable returns (uint){
+        return this.balance;
+    }
+
+    function calculateRunway() returns (uint)
+    {
+        return this.balance/salary;
+    }
+
+    function hasEnoughFund() returns(bool)
+    {
+        return calculateRunway()>0;
+    }
+
+    function getPaid()
+    {
+        if(msg.sender != employee)
+        {
+            revert();
+        }
+
+        uint nextPayday = lastPayday+payDuration;
+        if(nextPayday>now){
+            revert();
+        }
+        lastPayday = nextPayday;
+        employee.transfer(salary);
+    }
+}

Lesson-2/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

Lesson-2/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
+

Lesson-2/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

Lesson-2/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() {
+    }
+}

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/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/lesson3.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;
+    address owner;
+    uint totalSalary = 0;
+
+    modifier onlyOwner{
+        require(msg.sender == owner);
+        _;
+    }
+
+    modifier employeeExist(address employeeId){
+        var employee = employees[employeeId];
+        assert(employee.id == 0x0);
+        _;
+    }
+
+    //Employee[] employees;
+    //构造函数
+    function Payroll(){
+        owner = msg.sender;
+    }
+
+    function partialPaid(Employee employee) private{
+        uint payment = employee.salary * (now - employee.lastPayday)/payDuration;
+        employee.id.transfer(payment);
+    }
+
+
+    //mapping(address => Employee) employees;
+    mapping(address => Employee) public employees;
+
+
+   /*    
+   function findEmployee(address employee) private returns(Employee,uint) {
+        for(uint i= 0; i< employees.length; i++){
+            if(employees[i].id == employee){
+                return (employees[i],i);
+            }
+
+        }
+    }*/
+
+    //onlyOwner use
+    function addEmployee(address employeeId,uint salary) onlyOwner
+    {
+        //require(msg.sender == owner);
+        //var (employee,index) = findEmployee(employeeId);
+        var employee = employees[employeeId];
+        //solidity循环
+        /*for(uint i= 0; i< employees.length; i++){
+            if(employees[i].id == employee){
+                revert();
+            }
+        }*/
+        //Employee memory employee = findEmployee(employeeId);
+        assert(employee.id == 0x0);
+        totalSalary+=salary * 1 ether;
+        employees[employeeId]=Employee(employeeId,salary* 1 ether,now);
+        //employees.push((employee,salary,now));
+    }
+
+
+    /*   
+    function addEmployee(address employeeId,uint salary)
+    {
+        require(msg.sender == owner);
+        //var (employee,index) = findEmployee(employeeId);
+        var employee = employees[employeeId];
+        //solidity循环
+        for(uint i= 0; i< employees.length; i++){
+            if(employees[i].id == employee){
+                revert();
+            }
+        }
+        //Employee memory employee = findEmployee(employeeId);
+        //assert(employee.id == 0x0);
+        //totalSalary+=salary * 1 ether;
+        //employees[employeeId]=Employee(employeeId,salary* 1 ether,now);
+        //employees.push((employee,salary,now));
+    }
+    */
+
+    function removeEmployee(address employeeId)
+    {
+        require(msg.sender == owner);
+        //var (employee,index) = findEmployee(employeeId);
+        var employee = employees[employeeId];
+        assert(employeeId != 0x0);
+        //partialPaid(employee[index]);
+        partialPaid(employee);
+        //delete employee[index];
+        totalSalary-=employees[employeeId].salary;
+        delete employees[employeeId];
+ /*     employees[index] = employees[employees.length-1];
+        employees.length -=1;*/
+    }
+
+
+    function updateEmployee(address employeeId,uint salary){
+        require(msg.sender==owner);
+        var employee = employees[employeeId];
+        //var (employee,index) = findEmployee(employeeId);
+        assert(employee.id != 0x0);
+        /*       
+        partialPaid(employees[index]);
+        employees[index].salary = salary;
+        employees[index].lastPayday = now;*/
+        partialPaid(employee);
+        totalSalary-=employees[employeeId].salary;
+        employees[employeeId].salary = salary * 1 ether;
+        totalSalary+=employees[employeeId].salary;
+        employees[employeeId].lastPayday = now;
+    }
+
+    function addFund() payable returns(uint){
+        return this.balance;
+    }
+
+    function calculateRunway() returns (uint)
+    {
+/*        for (uint i=0;i < employees.length ;i++){
+            totalSalary+=employees[i].salary;
+        }*/
+        return this.balance/totalSalary;    
+    }
+
+    function hasEnoughFund() returns(bool)
+    {
+        return calculateRunway()>0;
+    }
+    //员工信息
+    /*    
+    function checkEmployee(address employeeId) returns(uint,uint)
+    {
+        var employee = employees[employeeId];
+        return(employee.salary,employee.lastPayday);
+    }*/
+
+    function checkEmployee(address employeeId) returns(uint salary,uint lastPayday)
+    {
+        var employee = employees[employeeId];
+        //return(employee.salary,employee.lastPayday);
+        salary = employee.salary;
+        lastPayday = employee.lastPayday;
+    }
+
+    function getPaid() employeeExist(msg.sender)
+    {
+        var employee = employees[msg.sender];
+        //assert(employee.id!=0x0);
+        uint nextPayday = employee.lastPayday + payDuration;
+        assert(nextPayday<now);
+        employees[msg.sender].lastPayday = nextPayday;
+        employee.id.transfer(employee.salary);
+    }
+
+}

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