自己建立類（時鐘,鬼怪）

時鐘走動

package day20150430;
/**
 * 時鐘走動
 * @author 谷振東
 *
 */
public class Clock {
    private int hour;
    private int minute;
    private int second;
    /**
     * 走起來
     */
    public void go(){
        second += 1;
        if (second ==60) {
            second = 0;
            minute += 1;
            if (minute == 60) {
                minute = 0;
                hour += 1;
                if (hour == 24) {
                    hour = 0;
                }
            }
        }   
    } 


    /**
     * 顯示時間
     */
    public void display(){
        System.out.println(hour + ":" + minute + ":" + second );
    }
    public void setHour(boolean up){
        if (up) {
            hour += 1;
            if(hour == 24){
                hour = 0;
            }
        }
        else {
            hour -= 1;
            if (hour == -1) {
                hour = 23;
            }
        }
    }
    public void setMinute (boolean up){
        if (up) {
            minute += 59;
            if(minute == 59){
                minute = 0;
            }
        }
        else {
            minute -= 1;
            if(minute == -1){
                minute = 59;
            }
        }
    }
    public void setSecond(boolean up){
        if (up) {
            second += 59;
            if (second == 59) {
                second = 0;
            }
        }
        else {
            second -= 1;
            if (second == -1) {
                second = 59;
            }
        }
    }
}

鬼怪抽象類

package day20150430;
/**
 * 鬼怪
 * @author 谷振東
 *
 */
public class Ghost {
    double top;//外觀高大
    String color;//顏色黑色
/**
 * 飛
 * @param fly 飛行
 */
public void fly (String fly ){
    System.out.println("飛起來了。"+ fly);   
    }
/**
 * 跳
 * @param jump 跳躍
 */
public void jump (String jump){
    System.out.println("跳"+ jump);
    }
}