카이 호스트만의 코어 자바8 2장 연습문제 일부 코드

연습문제 답

일부 중요하거나 풀어보고 싶은 문제만 풀었으며, 그에 대한 나의 코드를 공개한다.

9번 문제

연비가 설정되고 기름을 넣고 이동하는 자동차 클래스를 작성하는것.
연습문제를 기반으로 나의 생각을 조금 덧붙여 코드를 작성하였다.

/**
 * Created by sanghyoun on 2017. 3. 21..
 */
public class Ch2_9 {
    public static void main(String[] args) {
        Car car1 = new Car();
        car1.fillOil(10);
        car1.drive(50);
        car1.setKmPliter(20);
        car1.drive(100);
        car1.drive(100);
        car1.fillOil(5);
        car1.drive(100);
        System.out.println(String.format("Current Efficiency : %.1f ", car1.getEfficiency() ));
    }
}

class Car {
    private double oilTank;
    private double kmPliter;
    private double usedOil;
    private int startPoint;
    private int currentPoint;

    public Car() {
        this.oilTank = 0;
        this.kmPliter = 10;
        this.startPoint = 0;
        this.currentPoint = this.startPoint;
    }

    public void setKmPliter(double num) {
        this.kmPliter = num;
    }

    public double fillOil(double liter) {
        return this.oilTank += liter;
    }

    public int drive(int distance) {
        double oilNeed = distance / this.kmPliter;
        if (oilNeed <= this.oilTank) {
            this.oilTank -= oilNeed;
            this.usedOil += oilNeed;
            return this.currentPoint += distance;
        } else {
            double moveableDistance = this.oilTank * this.kmPliter;
            oilNeed = moveableDistance / this.kmPliter;
            this.oilTank -= oilNeed;
            this.usedOil += oilNeed;
            System.out.println("More Oil Need : " + (distance - moveableDistance) / this.kmPliter);
            return this.currentPoint += moveableDistance;
        }
    }

    public double getEfficiency() {
        return this.currentPoint / this.usedOil;
    }
}