import java.text.DecimalFormat;

public class MyTime {

	private int hour=0;
	private int minute=0;
	private int second=0;
	
	public MyTime(){
		
	} 
	public MyTime(int hour,int minute,int second){
		this.hour=hour;
		this.minute=minute;
		this.second=second;
	}
	public void setTime(int hour,int minute,int second){
		this.hour=hour;
		this.minute=minute;
		this.second=second;
	}
	public int getHour(){
		return hour;
	}
	public int getMinute(){
		return minute;
	}
	public int getSecond(){
		return second;
	}
	public void setHour(int hour){
		this.hour=hour;
	}
	public void setSecond(int second){
		this.second=second;
	}
	public void setMinute(int minute){
		this.minute=minute;
	}
	
	public String toString(){
		DecimalFormat df = new DecimalFormat("##00");
		return df.format(hour)+":"+df.format(minute)+":"+df.format(second);
		
	}
	
	public MyTime nextSecond(){
		this.second++;
		if(this.second==60){
			this.minute++;
			this.second=0;
		}
		if(minute==60){
			minute=0;
			hour++;
		}
		if(hour==24){
			hour=0;
		}
		return this;
	}
	public MyTime nextMinute(){
		this.minute++;
		if(minute==60){
			hour++;
			minute=0;
		}if(hour==24){
			hour=0;
		}
		return this;
	}
	public MyTime nextHour(){
		hour++;
		if(hour==24){
			hour=0;
		}
		return this;
	}
	
	
	public MyTime previousSecond(){
		second--;
		if(second==-1){//当second==0;- 1==-1就赋值；就完成了循环样式，只执行一次。1-59.
			second=59;
			minute--;
		}
		if(minute==-1){
			minute=59;
			hour--;
		}
		if(hour==23){
			hour=23;
		}
		return this;
	}
	public MyTime previousMinute(){
		minute--;
		if(minute==59){
			minute=59;
			hour--;
		}
		if(hour==23){
			hour=23;
		}
		return this;
	}
	public MyTime previousHour(){
		hour--;
		if(hour==23){
			hour=23;
		}
		return this;
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		MyTime my = new MyTime(23,59,0);
		System.out.println(my.previousSecond());
		
	}

}