Java构造方法，类与对象

Question

Answer 1

public class Test {
    public static void main(String[] args) {
        Rectangle rectangle = new Rectangle(30, 40);
        double computCircum = rectangle.computCircum();
        System.out.println("computCircum = " + computCircum);
        double computArea = rectangle.computArea();
        System.out.println("computArea = " + computArea);
    }
}


class Rectangle {
    private double width;
    private double height;

    public Rectangle() {
    }

    public Rectangle(double width, double height) {
        this.width = width;
        this.height = height;
    }

    public double computCircum() {
        return (width + height) * 2;
    }

    public double computArea() {
        return width * height;
    }
}