30天学会JAVA—练习题(2021韩顺平)——Day9

Test Demo Rose Jack John Jack

class BankAccount{
   
	private int balance;

	public BankAccount(int balance) {
   
		super();
		this.balance = balance;
	}
	
	
	public int getBalance() {
   
		return balance;
	}

	public void setBalance(int balance) {
   
		this.balance = balance;
	}

	public void deposit(double amount){
   
		balance += amount;
	}
	
	
	public void withdraw(double amount){
   
		balance -= amount;
	}
}

class CheckingAccount extends BankAccount{
   

	public CheckingAccount(int balance) {
   
		super(balance);
	}
	
	@Override
	public void deposit(double amount) {
   
		super.deposit(amount-1);
	}
	
	@Override
	public void withdraw(double amount) {
   
		super.withdraw(amount+1);
	}
	
}

class SavingsAccount extends BankAccount{
   
	private double rate = 0.01;
	private int count = 3;
	

	public double getRate() {
   
		return rate;
	}


	public void setRate(double rate) {
   
		this.rate = rate;
	}


	public int getCount() {
   
		return count;
	}


	public void setCount(int count) {
   
		this.count = count;
	}
	public SavingsAccount(int balance) {
   
		super(balance);
	}
	
	@Override
	public void deposit(double amount) {
   
		// 判断是否还有免手续费的机会
		if(count > 0){
   
			super.deposit(amount);
		}else{
   
			super.deposit(amount - 1);
		}
		count--;
	}
	
	@Override
	public void withdraw(double amount) {
   
		// 判断是否还有免手续费的机会
		if(count > 0){
   
			super.withdraw(amount);
		}else{
   
			super.withdraw(amount + 1);
		}
		count--;
	}
	
	public void earnMonthlyInterest(){
   //每个月初,统计上个月的利息,同时将count = 3
		count = 3;
		super.deposit(getBalance() * rate);
	}		
}

9. 代码

class Point{
   
	private double x;
	private double y;
	
	public Point(double x, double y) {
   
		super();
		this.x = x;
		this.y = y;
	}

	public double getX() {
   
		return x;
	}

	public void setX(int x) {
   
		this.x = x;
	}

	public double getY() {
   
		return y;
	}

	public void setY(int y) {
   
		this.y = y;
	}
}

class LabeledPoint extends Point{
   
	private String label;

	public LabeledPoint(double x, double y, String label) {
   
		super(x, y);
		this.label = label;
	}

	public String getLabel() {
   
		return label;
	}

	public void setLabel(String label) {
   
		this.label = label;
	}	
}

10.代码

class Doctor{
   
	private String name;
	private int age;
	private String job;
	private char gender;
	private int sal;
	
	public Doctor(String name, int age, String job, char gender, int sal) {
   
		super();
		this.name = name;
		this.age = age;
		this.job = job;
		this.gender = gender;
		this.sal = sal;
	}

	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 String getJob() {
   
		return job;
	}

	public void setJob(String job) {
   
		this.job = job;
	}

	public char getGender() {
   
		return gender;
	}

	public void setGender(char gender) {
   
		this.gender = gender;
	}

	public int getSal() {
   
		return sal;
	}

	public void setSal(int sal) {
   
		this.sal = sal;
	}
	
	@Override
	public boolean equals(Object obj) {
   
		if(obj instanceof Doctor){
   //判断是否为Doctor类
			if((((Doctor) obj).name.equals(name) &&
					((Doctor) obj).age == age &&
					((Doctor) obj).job.equals(job)&&
					((Doctor) obj).gender == gender&&
					((Doctor) obj).sal == sal)){
   
				return true;
			}		
		}
		return false;
	}	
}
public class Test {
   	
	public static void main(String[] args) {
   
		Doctor doctor1 = new Doctor("jack", 34, "doctor", '男', 2000);
		Doctor doctor2 = new Doctor("jack", 34, "doctor", '男', 2000);
		System.out.println(doctor1.equals(doctor2));
	}		
}

/** * 从子类一步步查找,若没有,到父类查找 * 动态绑定 * 调用方法时,看运行类型;调用属性时,哪里声明,哪里使用 */
//向上转型[父类的引用指向子类的对象] 左编译,右运行
Person person = new Student();
/* * 可调能调用父类的方法[编译类型Person] * 可调用Person.run(),Person.eat() * 输出 :student run[动态绑定], person eat */

//向下转型[强制转型](先向上转型之后,才可以向下转型)
Student student = (Student) person;
/* * 可调用父类和子类的方法[编译类型Student] * 可调用Student.eat(),Student.run(),Student.study() * 输出:person eat,student run,student study */