向嵩-123-Samxiang2011-第三次作业

Lesson-1/assignment/yours.sol

@@ -1 +1,50 @@
 /*作业请提交在这个目录下*/
+pragma solidity ^0.4.14;
+
+contract Payroll {
+    uint constant payDuration = 10 seconds;
+
+    address owner;
+    uint salary;
+    address employee;
+    uint lastPayday;
+
+    function Payroll() {
+        owner = msg.sender;
+    }
+
+    function updateEmployee(address e, uint s) {
+        require(msg.sender == owner);
+
+        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() {
+        require(msg.sender == employee);
+
+        uint nextPayday = lastPayday + payDuration;
+        assert(nextPayday < now);
+
+        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/assignment/yours.sol

@@ -0,0 +1,87 @@
+/*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;
+    Employee[] employees;
+
+    function Payroll() {
+        owner = msg.sender;
+    }
+
+    function _partialPaid(Employee employee) private {
+        uint payment = employee.salary * (now - employee.lastPayday) / payDuration;
+        employee.id.transfer(payment);
+    }
+
+    function _findEmployee(address employeeId) private returns (Employee, uint) {
+        for(uint i = 0; i < employees.length; i++){
+            if (employees[i].id == employeeId){
+                return (employees[i], i);
+            }
+        }
+    }
+
+    function addEmployee(address employeeId, uint salary) {
+        require(msg.sender == owner);
+        var (emloyee, index) = _findEmployee(employeeId);
+        assert(emloyee.id == 0x0);
+        employees.push(Employee(employeeId, salary * 1 ether, now));
+    }
+
+    function removeEmployee(address employeeId) {
+        require(msg.sender == owner);
+        var (employee, index) = _findEmployee(employeeId);
+        assert(employee.id != 0x0);
+
+        _partialPaid(employee);
+        delete employees[index];
+        employees[index] = employees[employees.length - 1];
+        employees.length -= 1;
+    }
+
+    function updateEmployee(address employeeId, uint salary) {
+        require(msg.sender == owner);
+        var (employee, index) = _findEmployee(employeeId);
+        assert(employee.id != 0x0);
+
+        _partialPaid(employee);
+        employee.salary = salary;
+        employee.lastPayday = now;
+    }
+
+    function addFund() payable returns (uint) {
+        return this.balance;
+    }
+
+    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) {
+        return calculateRunway() > 0;
+    }
+
+    function getPaid() {
+        var (employee, index) = _findEmployee(msg.sender);
+        assert(employee.id != 0x0);
+
+        uint nextPayday = employee.lastPayday + payDuration;
+        assert (nextPayday < now);
+
+        employee.lastPayday = nextPayday;
+        employee.id.transfer(employee.salary);
+    }
+}

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

@@ -0,0 +1,50 @@
+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/yours.sol

@@ -0,0 +1,83 @@
+/*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;
+
+    address owner;
+    mapping(address => Employee) employees;
+
+    function Payroll() {
+        owner = msg.sender;
+    }
+
+    function _partialPaid(Employee employee) private {
+        uint payment = employee.salary * (now - employee.lastPayday) / payDuration;
+        employee.id.transfer(payment);
+    }
+
+
+    function addEmployee(address employeeId, uint salary) {
+        require(msg.sender == owner);
+        var emloyee = employees[employeeId];
+        assert(emloyee.id == 0x0);
+        totalSalary += salary * 1 ether;
+        employees[employeeId] = Employee(employeeId, salary * 1 ether, now);
+    }
+
+    function removeEmployee(address employeeId) {
+        require(msg.sender == owner);
+        var employee = employees[employeeId];
+        assert(employee.id != 0x0);
+
+        _partialPaid(employee);
+        totalSalary -= employees[employeeId].salary;
+        delete employees[employeeId];
+
+    }
+
+    function updateEmployee(address employeeId, uint salary) {
+        require(msg.sender == owner);
+        var employee = employees[employeeId];
+        assert(employee.id != 0x0);
+
+        _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) {
+        return this.balance / totalSalary;
+    }
+
+    function hasEnoughFund() returns (bool) {
+        return calculateRunway() > 0;
+    }
+
+
+    function getPaid() {
+        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

@@ -0,0 +1,3 @@
+## 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