冒泡排序

用冒泡算法实现对日期的排序

//日期类，包含年月日的信息。重写toString
//方法，输出年月日信息。
public class Date {

    public int year ,month,day;
    
    public Date(int year,int month,int day){
        this.year = year;
        this.month = month;
        this.day = day;
    }
    
    public String toString(){
        return "year,month,day:"+year+" "+month+" "+day;
    }
}

public class TestBubbleSort {

    public static void main(String[] args){
        
        Date[] dates = new Date[5];
        
        dates[0] = new Date(2012,6,1);
        dates[1] = new Date(2013,6,2);
        dates[2] = new Date(2012,7,3);
        dates[3] = new Date(2013,6,1);
        dates[4] = new Date(2012,7,2);
        
        BubbleSort(dates);
        
        for(int i = 0;i<dates.length;i++){
            System.out.println(dates[i].toString());
        }
    }
    

//Compare方法，若d1<d2返回-1,d1=d2返回0，否则返回1.
    public static int Compare(Date d1,Date d2){
        
        if(d1.year>d2.year ){
            return 1;
        }else if (d1.year < d2.year ){
            return -1;
        }else if(d1.month > d2.month){
            return 1;
        }else if(d1.month < d2.month ){
            return -1;
        }else if(d1.day > d2.day ){
            return 1;
        }else if(d1.day < d2.day ){
            return -1;
        }else{
            return 0;
        }
    }
    
    public static Date[] BubbleSort(Date[] dates){
        int length = dates.length;
        Date temp = null;
        
        for(int i = length-1;i>=1;i--){
            for(int j = 0;j<i;j++){
                if(Compare(dates[j],dates[j+1])==1){
                    temp = dates[j];
                    dates[j] = dates[j+1];
                    dates[j+1] = temp;
                }
            }
        }
        
        return dates;
    }
}