Lesson_for_java_day10--练习

练习一：

package sonyi;
/*
练习:
定义一个表示学生的类。属性有：学号，姓名，年龄，计算机成绩，数学成绩，英语成绩。
要求学号为类变量，每次增加学生时，学号自动增加，并赋值给新增学生。计算学生的平均成绩和总成绩。
实例化几个对象，并测试。
*/
public class StudentTest {
public static void main(String[] args) {

//创建学生类，学号自动增加，其他参数由构造方法传入
Student s1 = new Student("zhangsan",20,95,80,78);
Student s2 = new Student("lisi",20,95,80,78);
System.out.println(s1);//打印对象就是打印对象的toString方法。
System.out.println(s2);

//设置学生学号从10开始
Student.index = 10;
Student s3 = new Student("lisi",27,95,80,78);
System.out.println(s3);
Student s4 = new Student("lisi",27,95,80,78);
System.out.println(s4);
}
}

class Student{
static int index = 1;//定义一个静态变量，用来记录当前新增学生的学号
//定义私有成员变量
private String name;
private int age;
private int num;
private double computerScore;
private double mathScore;
private double englisdScore;

Student(){
}

//重载构造方法，传入实参
Student(String name,int age,double computerScore,double mathScore,double englisdScore){
this.name= name;
this.age = age;
this.computerScore = computerScore;
this.mathScore = mathScore;
this.englisdScore = englisdScore;
num = index++;//将当前学号赋给当前创建的学生对象，并且将学号自增1，用来赋给下一个创建的学生对象；
}

//计算每个学生的平均成绩
public double averScore(){
return Math.round((computerScore + mathScore + englisdScore)/3);// 四舍五入
}

//计算每个学生的总成绩
public double sumScore(){
return computerScore + mathScore + englisdScore;
}

//复写toString()方法，用来输出学生的信息
@Override
public String toString() {
return "Student [学号：" + num + ",姓名：" + name + ",年龄：" + age +
",计算机成绩：" + computerScore+ ",数学成绩：" + mathScore + ",英语成绩" + englisdScore +
"，各科平均成绩：" + averScore() + ",各科总成绩：" + sumScore() + "]";
}

//定义各私有成员变量的获取方法和设置方法
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public double getComputerScore() {
return computerScore;
}
public void setComputerScore(double computerScore) {
this.computerScore = computerScore;
}
public double getMathScore() {
return mathScore;
}
public void setMathScore(double mathScore) {
this.mathScore = mathScore;
}
public double getEnglisdScore() {
return englisdScore;
}
public void setEnglisdScore(double englisdScore) {
this.englisdScore = englisdScore;
}
}


练习二：
package sonyi;
/*
练习:
定义一个表示雇员的类。属性有：雇员编号，姓名，职位，月薪，奖金。
要求雇员编号为类变量，每次增加成员时，编号自动增加，并赋值给新增成员。计算雇员的月薪和年薪，打印雇员全部信息。
实例化几个对象，并测试。
*/
public class EmployeeTest {

public static void main(String[] args) {
// TODO Auto-generated method stub
//类的实例化，并赋初始值
Employee e1 = new Employee("张三","前台",2000,500);
Employee e2 = new Employee("小张","工程师",2000,500);
Employee e3 = new Employee("小李","售后",2000,500);
Employee e4 = new Employee("李四","前台",2000,500);
Employee e5 = new Employee("王五","程序员",8000,1000);

//打印类信息
System.out.println(e1);
System.out.println(e2);
System.out.println(e3);
System.out.println(e4);
System.out.println(e5);
}
}

class Employee{
//静态属性，记录新增成员编号，并赋值给新增成员，赋值后自加1
private static int index = 1;
private int no;//定义私有属性
private String name;
private String position;
private double salary;
private double premium;

Employee(){

}

//重载构造方法
Employee(String name, String position,double salary,double premium){
this.name = name;
this.position = position;
this.salary = salary;
this.premium = premium;
no = index++;
}

//复写toString，打印成员信息
@Override
public String toString() {
return "Employee [雇员编号：" + no + ", 姓名：" + name + ", 职位："
+ position + ", 基本工资：" + salary + ", 奖金" + premium
+ ", 月薪" + monthPay() + ", 年薪：" + annualPay() + "]";
}

//定义私有属性的获取方法和设置方法
public double monthPay(){
return salary + premium;
}
public double annualPay(){
return monthPay()*12;
}

//定义私有属性的获取方法和设置方法
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getNo() {
return no;
}
public void setNo(int no) {
this.no = no;
}
public String getPosition() {
return position;
}
public void setPosition(String position) {
this.position = position;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
public double getPremium() {
return premium;
}
public void setPremium(double premium) {
this.premium = premium;
}
}