ex4.java

讲述各种各样的java初始编程 了解编程

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package chenchao3;



/**
 *
 * @author williechen
 */
public class Ex4 {
}

interface Centered {

    void setCenter(double x, double y);

    double getCenterX();

    double getCenterY();
}

class CenteredRectangle extends Rectangle implements Centered {
    // New instance fields
    private double cx,  cy;

    // A constructor
    public CenteredRectangle(double cx, double cy, double w, double h) {
        super(w, h);
        this.cx = cx;
        this.cy = cy;
    }

    // We inherit all the methods of Rectangle but must
    // provide implementations of all the Centered methods. 
    public void setCenter(double x, double y) {
        cx = x;
        cy = y;
    }

    public double getCenterX() {
        return cx;
    }

    public double getCenterY() {
        return cy;
    }
}

class CenteredCircle extends Circle implements Centered {
    // New instance fields
    private double cx,  cy;

    // A constructor
    public CenteredCircle(double cx, double cy, double r) {
        super(r);
        this.cx = cx;
        this.cy = cy;
    }

    // We inherit all the methods of Rectangle but must
    // provide implementations of all the Centered methods. 
    public void setCenter(double x, double y) {
        cx = x;
        cy = y;
    }

    public double getCenterX() {
        return cx;
    }

    public double getCenterY() {
        return cy;
    }
}