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java基础练习——类的设计和对象的创建、成员变量和成员方法的设计

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Java

和之前一样，依旧以题为例为大家讲述java类的设计和对象的创建、成员变量和成员方法的设计，欢迎大家交流讨论、
1、Point类例子(1)
请将下面程序的【代码】替换为Java程序代码，使程序运行正确。

文件Main.java
import java.util.Scanner;
public class Main {
    public static void main(String args[]) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        Point pt = 【代码1】 Point(1, n);// 创建对象
        System.out.println("pt.x=" + 【代码2】.x);// 取
        pt.x = 5;// 修改
        System.out.println("pt.x=" + pt.x);
        pt.move(3, 3);// 移动
        System.out.println("pt.x=" + pt.x);
        System.out.println("pt.y=" + pt.y);
        【代码3】 pt2 = new Point();// 声明对象并new
        System.out.println("pt2.x=" + pt2.x);
        pt2 = new Point(9, 2);
        System.out.println("pt2.x=" + pt2.x);
    }
}
class Point {
    int x, y;// 成员变量,属性
    【代码4】 Point() {// 无参构造方法
        x = 0;
        y = 0;
    }
    public Point(int ix, int 【代码5】) {// 有参构造方法
        x = ix;
        y = iy;
    }
    【代码6】 move(int ix, int iy) {// 方法
        x += ix;// x=x+ix
        y += iy;
    }
}

解题

import java.util.Scanner;
public class Main {
    public static void main(String args[]) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        Point pt = new Point(1, n);// 创建对象
        System.out.println("pt.x=" + pt.x);// 取
        pt.x = 5;// 修改
        System.out.println("pt.x=" + pt.x);
        pt.move(3, 3);// 移动
        System.out.println("pt.x=" + pt.x);
        System.out.println("pt.y=" + pt.y);
        Point pt2 = new Point();// 声明对象并new
        System.out.println("pt2.x=" + pt2.x);
        pt2 = new Point(9, 2);
        System.out.println("pt2.x=" + pt2.x);
    }
}
class Point {
    int x, y;// 成员变量,属性
    public Point() {// 无参构造方法
        x = 0;
        y = 0;
    }
    public Point(int ix, int iy) {// 有参构造方法
        x = ix;
        y = iy;
    }
    public void move(int ix, int iy) {// 方法
        x += ix;// x=x+ix
        y += iy;
    }
}

类描述图
类名称	Point
成员变量	int x,y
成员方法	void move(int is,int iy)
构造方法	Point() Point(int ix,int iy)

2、类的基本操作简单例子

文件Main.java
public class Main {
    public static void main (String args[ ]) {
       【代码1】//命令行窗口输出"教学活动从教室开始"
       Teacher zhang = new Teacher();
       Student jiang = 【代码2】Student();//创建对象
       zhang.introduceSelf();
       jiang.【代码2】; //调用它的方法
    }
}
class Teacher {
  void introduceSelf() {
     【代码3】    //命令行窗口输出"我是李老师"
   }
}
 
class Student {
  void introduceSelf() {
     【代码4】/ /命令行窗口输出"我是学生,名字是:奖励"
   }
}

解题

public class Main {
    public static void main (String args[ ]) {
       System.out.println("教学活动从教室开始");//命令行窗口输出"教学活动从教室开始"
       Teacher zhang = new Teacher();
       Student jiang = new Student();//创建对象
       zhang.introduceSelf();
       jiang.introduceSelf(); //调用它的方法
    }
}
class Teacher {
  void introduceSelf() {
     System.out.println("我是李老师");    //命令行窗口输出"我是李老师"
   }
}
 
class Student {
  void introduceSelf() {
	  System.out.println("我是学生,名字是:奖励");//命令行窗口输出"我是学生,名字是:奖励"
   }
}

类描述图
类名称	Teacher
成员方法	introduceSelf()
类名称	Student
成员方法	introduceSelf()

3、关于Point类的操作(2)
下面程序构造一个类来描述屏幕上的一个点，该类的构成包括点的 x 和 y 两个坐标，以及一些对点进行的操作，包括：取得点的坐标值，对点的坐标进行赋值，编写应用程序生成该类的对象并对其进行操作。

文件Main.java
 public class Main {
 
public static void main(String[] args) {
Point Point1 = new Point(3, 4);
System.out.println("Point1:" + "(" +
Point1.x + "," + Point1.y + ")");
 
Point Point2 = Point1.getPoint();
System.out.println("Point2:" + "(" +
Point2.x + "," + Point2.y + ")");
 
Point 【代码1】 = new Point(5, 6);
Point1.setPoint(Point3);
System.out.println("Point1:" + "(" +
Point1.x + "," + Point1.y + ")");
}
}
 
class Point {
int x, y;
 
public Point(int x, 【代码2】) {
this.x = x;
this.y = y;
}
 
【代码3】 Point getPoint() {
Point tempPoint = new Point(x, y);
return tempPoint;
}
 
public void setPoint(Point point) {
this.x = point.x;
【代码4】y = point.y;
}
}

解题

public class Main {
 
public static void main(String[] args) {
Point Point1 = new Point(3, 4);
System.out.println("Point1:" + "(" +
Point1.x + "," + Point1.y + ")");
 
Point Point2 = Point1.getPoint();
System.out.println("Point2:" + "(" +
Point2.x + "," + Point2.y + ")");
 
Point Point3 = new Point(5, 6);
Point1.setPoint(Point3);
System.out.println("Point1:" + "(" +
Point1.x + "," + Point1.y + ")");
}
}
 
class Point {
int x, y;
 
public Point(int x, int y) {
this.x = x;
this.y = y;
}
 
public Point getPoint() {
Point tempPoint = new Point(x, y);
return tempPoint;
}
 
public void setPoint(Point point) {
this.x = point.x;
this.y = point.y;
}
 
}

类名称	Point
成员变量	Int x,y
成员方法	getPoint() setPoint(Point point)
构造方法	Point(int x,inty)

4、关于Point类的操作(3)
下面程序构造一个类来描述屏幕上的一个点，该类的构成包括点的 x 和 y 两个坐标，以及一些对点进行的操作，包括：取得点的坐标值，对点的坐标进行赋值，编写应用程序生成该类的对象并对其进行操作。

文件Main.java
 
public class Main {
 
public static void main(String[] args) {
// TODO Auto-generated method stub
Point origin = new 【代码1】(10, 10);
origin.getPoint();
【代码2】.setPoint(20, 20);
origin.getPoint();
}
 
}
 
class Point {
private int x;
private int y;
 
public Point(int x, int y) {
this.x = x;
【代码3】y = y;
}
 
public void setPoint(int x1, int y1) {
x = x1;
y = y1;
}
 
public void getPoint() {
System.out.println("Point x: " + x + ",y: " + y);
}
 
}

解题

public class Main {
 
public static void main(String[] args) {
// TODO Auto-generated method stub
Point origin = new Point(10, 10);
origin.getPoint();
origin.setPoint(20, 20);
origin.getPoint();
}
 
}
 
class Point {
private int x;
private int y;
 
public Point(int x, int y) {
this.x = x;
this.y = y;
}
 
public void setPoint(int x1, int y1) {
x = x1;
y = y1;
}
 
public void getPoint() {
System.out.println("Point x: " + x + ",y: " + y);
}
 
}

类名称	Point
成员变量	private int x; private int y;
成员方法	setPoint(int x1, int y1) getPoint()
构造变量	Point(int x, int y)

5、按面向对象要求编程在Employee加入身份证
下面程序在Employee类中加入身份证信息,但类Employee中部分代码缺失.请编写程序代码，使程序运行正确。

文件Main.java
 
import java.util.*;
public class Main {
 public static void main(String args[]) {
  Scanner reader = new Scanner(System.in);
  String name=reader.nextLine();
  String ID=reader.nextLine();
  int salary= reader.nextInt();
  int year = reader.nextInt();
  int month=reader.nextInt();
  int day=reader.nextInt();  
Employee e = new Employee(name,ID,salary,year,month,day);
e.raiseSalary(5);
System.out.println("姓名:"+e. getName()+ " 身份证:" +e.getID()+" 工资:"+ e.getSalary());
  System.out.println("The Main class is end.");
 }
}
 
class Employee {
  private String name;//私有域,姓名
  private String ID;//私有域,身份证
  private double salary;//私有域,工资
  private Date hireDay; //私有域,录用日期
  //构造方法
  public Employee(String n, double s, int year, int month, int day)
  {
     name = n;//参数,(局部)变量
     salary = s;//参数, (局部)变量
     GregorianCalendar calendar = new GregorianCalendar(year, month - 1, day);
     // GregorianCalendar uses 0 for January(1月份是0)
     hireDay = calendar.getTime();
  }
 
public String getName() {
return name;
}
public double getSalary() {
return salary;
}
public Date getHireDay() {
return hireDay;
}
//"涨工资"计算
public void raiseSalary(double byPercent)
{
  double raise = salary * byPercent / 100;
  salary += raise;
}
 
}

输入：
姓名
身份证
工资
以空格分隔的日期，形式为YYYY MM DD
输出：
姓名:xxx 身份证:yyyyy 工资:d 这里xxx和yyyyy是字符串,d是double数
The Main class is end.

样例输入：
Romeo
430502199807101121
50000
2014 7 11
样例输出：
姓名:Romeo 身份证:430502199807101121 工资:52500.0
The Main class is end.
解题

import java.util.*;
public class Main {
 public static void main(String args[]) {
  Scanner reader = new Scanner(System.in);
  String name=reader.nextLine();
  String ID=reader.nextLine();
  int salary= reader.nextInt();
  int year = reader.nextInt();
  int month=reader.nextInt();
  int day=reader.nextInt();  
Employee e = new Employee(name,ID,salary,year,month,day);
e.raiseSalary(5);
System.out.println("姓名:"+e. getName()+ " 身份证:" +e.getID()+" 工资:"+ e.getSalary());
  System.out.println("The Main class is end.");
 }
}
 
class Employee {
  private String name;//私有域,姓名
  private String ID;//私有域,身份证
  private double salary;//私有域,工资
  private Date hireDay; //私有域,录用日期
  //构造方法
  public Employee(String n,String id, double s, int year, int month, int day)
  {
     name = n;//参数,(局部)变量
     salary = s;//参数, (局部)变量
     GregorianCalendar calendar = new GregorianCalendar(year, month - 1, day);
     // GregorianCalendar uses 0 for January(1月份是0)
     hireDay = calendar.getTime();
  }
 
public String getID() {
	// TODO Auto-generated method stub
	return ID;
}

public String getName() {
return name;
}

public double getSalary() {
return salary;
}
public Date getHireDay() {
return hireDay;
}
//"涨工资"计算
public void raiseSalary(double byPercent)
{
  double raise = salary * byPercent / 100;
  salary += raise;
}
 
}

类名称
成员变量	private String name; private String ID;private double salary; private Date hireDay;
成员方法	getID() getName() getSalary() getHireDay() raiseSalary(double byPercent)
构造方法	public Employee(String n,String id, double s, int year, int month, int day)