41_王硕_第六次作业

Lesson-2/assignment/payRoll.sol

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+1，	完成今天的智能合约添加100 Ethan到合约中，加入十个员工，每个员工的薪水都是1 Eth。
+
+2，	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？
+消耗 2 gas.
+
+
+3, Gas 变化吗？如果有，为什么？
+有变化，因为调用了智能合约的函数 calculateRunway。
+4， 如何优化 calculateRunway这个函数来减少gas的消耗？
+在函数中避免使用 this关键字。
+
+5，	提交：智能合约代码，gais的变化记录，calculateRunway函数的优化。
+pragma solidity ^0.4.14;
+contract Payroll {
+   struct Employee{
+       address id;
+       uint salary;
+       uint lastPayday;
+
+   }
+
+   uint constant payDuration = 5 seconds;
+   address owner;    
+   Employee[] employees;
+
+    function Payroll(){
+        //当前创建合约的人
+       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 (employee, index) = _findEmployee(employeeId);
+       //保证你想要加入的这个员工是之前没有的,如果员工已经存在，就没有必要再加一遍了
+       assert(employee.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) ;
+
+        //否则快付工资的时候老板直接把你remove掉，你这个月不是白干了嘛,防止黑心老板,删除员工信息前，如果没有到payDuration规定的结算日，但也做了工作，就要先结算清楚
+        _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 );
+        employees[index].salary = salary * 1 ether;
+        employees[index].lastPayday = now;
+   }
+
+   //往智能合约里加钱
+   function addFund() payable returns (uint) {
+        return this.balance;
+   }
+
+   // 返回钱能支付工资的次数
+   function calculateRunway() returns (uint){
+       uint totalSalary = 0 ;
+
+       for(uint i = 0; i < employees.length; i++ ){
+            totalSalary += employees[i].salary + totalSalary; 
+       }       
+       //当前可以支付多少次薪水
+       return this.balance / totalSalary ;
+   }
+
+   //查看在contract中工资的钱能否支持一个月的钱
+   function hasEnoughFund() returns(bool){
+       return calculateRunway() > 0;
+   }
+
+   //到了领工资日，就可以点击领取工资
+   function getPaid(){
+       var (employee, index) = _findEmployee(msg.sender);
+       assert(employee.id != 0x0) ;
+
+       uint nextPayDay = employee.lastPayday + payDuration;
+       assert(nextPayDay < now );
+
+       employees[index].lastPayday = nextPayDay ;
+       employees[index].id.transfer(employee.salary);              
+   }
+
+}

Lesson-3/assignment/41_王硕_第三次作业

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+pragma solidity ^0.4.14;
+
+contract Payroll {
+   struct Employee{
+       address id;
+       uint salary;
+       uint lastPayday;
+   }
+
+   uint constant payDuration = 5 seconds;
+   address owner;    
+   mapping(address => Employee) employees ;
+
+   uint totalSalary = 0 ;
+
+   function Payroll(){
+        //当前创建合约的人
+       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 employee = employees[employeeId];
+       //保证你想要加入的这个员工是之前没有的,如果员工已经存在，就没有必要再加一遍了
+       assert(employee.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) ;
+
+        //否则快付工资的时候老板直接把你remove掉，你这个月不是白干了嘛,防止黑心老板,删除员工信息前，如果没有到payDuration规定的结算日，但也做了工作，就要先结算清楚
+        _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 );
+       employees[employeeId].salary = salary * 1 ether;
+       employees[employeeId].lastPayday = now;
+   }
+
+   function changePaymentAddress(address oldEmployeeId, address newEmployeeId){
+       require(msg.sender == owner);
+       var employee = employees[oldEmployeeId];
+       assert(employee.id != 0x0) ;
+
+       employees[oldEmployeeId].id = newEmployeeId;
+   }
+
+   //往智能合约里加钱
+   function addFund() payable returns (uint) {
+        return this.balance;
+   }
+
+   // 返回钱能支付工资的次数
+   function calculateRunway() returns (uint){
+
+       //当前可以支付多少次薪水
+       return this.balance / totalSalary ;
+   }
+
+   //查看在contract中工资的钱能否支持一个月的钱
+   function hasEnoughFund() returns(bool){
+       return calculateRunway() > 0;
+   }
+
+   //到了领工资日，就可以点击领取工资
+   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-4/assignment/41_王硕_第四次作业

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+var Payroll = artifacts.require("./Payroll.sol");
+
+contract('Payroll', function(accounts) {
+
+    it("add employee successed !", function() {
+        return Payroll.deployed().then(function(instance) {
+           payrollInstance = instance;
+           return payrollInstance.addEmployee( accounts[1] , 1);  
+        }).then(function() {          
+
+            return payrollInstance.employees.call(accounts[1]);            
+        }).then(function(employee){
+            //console.log("*** employee.id => " + employee[0] );
+            employee1 = employee[0] ;
+        }).then(function(){
+            assert.equal(employee1, accounts[1]);
+        })           
+    });
+
+    it("remove employee successed !", function() {
+        return Payroll.deployed().then(function(instance) {
+           payrollInstance = instance;
+           //console.log("*** accounts[1] => " + accounts[1] );
+           return payrollInstance.removeEmployee( accounts[1] );  
+        }).then(function() { 
+            return payrollInstance.employees.call(accounts[1]);            
+        }).then(function(employee){          
+            removedEmployeeId = employee[0] ;
+          //  console.log("*** removed employee.id => " + employee[0] );
+        }).then(function(){
+            assert.equal(removedEmployeeId, 0 );            
+        })
+    });
+
+});

Lesson-5/README.md

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+## 硅谷live以太坊智能合约频道官方地址
+
+### 第五课
+
+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
+

Lesson-5/assignment/README.md

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+## 硅谷live以太坊智能合约 第五课作业
+这里是同学提交作业的目录