Chepter 06. 객체지향 프로그래밍 클래스 문제 (Circle, Time, Plane, NewCar)

문제 1

Circle

 

 

  

    
    
    
    
  
package z_homework.work6.circle;

public class Circle {

	double radius;
	double x;
	double y;

	public double getRadius() {
		return radius;
	}

	public void setRadius(double radius) {
		// if(radius <0) {
		// radius = 0;
		// }
		this.radius = radius;
		if (this.radius < 0) {
			this.radius = 0;
		}

	}

	public double getX() {
		return x;
	}

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

	public double getY() {
		return y;
	}

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

	Circle() {

	}

	public double getArea() {
		return Math.PI * Math.pow(this.radius, 2);
	}
}

 

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문제 2

Time

  

    
    
    
    
  
package z_homework.work6.time;

public class Time {

	private int hour;
	private int minute;
	private int second;

	public Time() {
		this.hour = 0;
		this.minute = 0;
		this.second = 0;
	}

	public Time(int hour, int minute, int second) {
		this.hour = hour;
		if (this.hour < 0 || this.hour > 23) {
			this.hour = 0;
		}
		this.minute = minute;
		if (this.minute < 0 || this.minute > 59) {
			this.minute = 0;
		}
		this.second = second;
		if (this.second < 0 || this.second > 59) {
			this.second = 0;
		}

	}

	public String toString() {
		return String.format("%02d:%02d:%02d", this.hour, this.minute, this.second);
	}
}

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문제 3

Plane

 

 

  

    
    
    
    
  
package z_homework.work6.plane;

public class Plane {

	String manufacture; // 제작
	String model; // 비행기모델
	int maxNumberOfPassengers; // 최대승객
	static int NumberOfPlanes; // 지금까지 생성된 비행기 객체의 수,
    			              //정적 변수로 선언 객체가 생성될때마다 생성자에서 증가시킴

	public Plane() {

		manufacture = "";
		model = "";
		maxNumberOfPassengers = 0;
		NumberOfPlanes++;

	}

	public static int getNumberOfPlanes() {
		return NumberOfPlanes;
	}

	public Plane(String manufacturer, String model, int maxNumberOfPassengers) {
		this.manufacture = manufacturer;
		this.model = model;
		this.maxNumberOfPassengers = maxNumberOfPassengers;
		NumberOfPlanes++;

	}

	public String getManufacture() {
		return manufacture;
	}

	public void setManufacture(String manufacture) {
		this.manufacture = manufacture;
	}

	public String getModel() {
		return model;
	}

	public void setModel(String model) {
		this.model = model;
	}

	public int getMaxNumberOfPassengers() {
		return maxNumberOfPassengers;
	}

	public void setMaxNumberOfPassengers(int maxNumberOfPassengers) {
		this.maxNumberOfPassengers = maxNumberOfPassengers;
		if (this.maxNumberOfPassengers < 0) {
			this.maxNumberOfPassengers = 0;
		}
	}

}

 

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문제 4

Car

 

  

    
    
    
    
  
package z_homework.work6.car;

public class Car {

	private double speed; // 현재속
	private String color; // 자동차 색
	final private static double MAX_SPEED = 200; // 최대 속력

	public Car() {

	}

	public Car(String color) {
		this.color = color;
	}

	public double getSpeed() {
		return speed;
	}

	public void setSpeed(double speed) {
		this.speed = speed;
	}

	public String getColor() {
		return color;
	}

	public void setColor(String color) {
		this.color = color;
	}

	public static double getMaxSpeed() {
		return MAX_SPEED;
	}

	public boolean speedUp(double speed) {
		double targetSpeed = this.speed + speed;
		if (speed < 0 || speed > MAX_SPEED) {
			return false;

		} else {
			this.speed = speed;
			return true;
		}
	}

	@Override
	public String toString() {
		return "Car [speed=" + speed + ", color=" + color + "]";
	}
}

 

 getter, setter를 활용한다.

보안을 위해 private으로 접근제한을 해놓았기 때문이다!