mycalendar.java

万年历

public class myCalendar {
	
	//以下程序段是用来计算输入日期为该年的第几天的
	
	public static int cptDay(int year , int month , int day){
		byte dayadd[]={1,-2,1,0,1,0,1,1,0,1,0,1};	//用来存储每个月天数和30的差值
		int daycount = 0;	//这是天数daycount计数器，初始化为0
			for(int i=0; i<month-1; i++)
				daycount+=(30+dayadd[i]);
			daycount+=day;
			return (month>2)?daycount+isLeap(year):daycount;
	}

	//闰年判定程序段，闰年返回1，平年返回0
	
	public static int isLeap(int year){
		if((year%400==0)||((year%4==0)&&(year%100!=0)))
			return 1;
		return 0;
	}
	
	//计算输入日期是星期几
	//采用了基姆拉尔森计算公式 
	//W= (d+2*m+3*(m+1)/5+y+y/4-y/100+y/400) mod 7 
	//在公式中d表示日期中的日数，m表示月份数，y表示年数。
	//注意：在公式中有个与其他公式不同的地方： 
	//把一月和二月看成是上一年的十三月和十四月，例：如果是2004-1-10则换算成：2003-13-10来代入公式计算。 
	
	public static int getWeek(int year,int month,int day){
		if(month<3)
		{ month+=12; year--;}
		return (day+2*month+3*(month+1)/5+year+year/4-year/100+year/400)%7;
	}
	
	//以下程序段是来计算输入日期为该年第几周的
	
	public static int weekCount(int year,int month,int day){
		int dayCnt = cptDay(year,month,day);
		int weekminus = getWeek(year,month,day)-getWeek(year,1,1);
		int weekCnt = 0;
		if(dayCnt%7==0) weekCnt = dayCnt/7+((weekminus>0)?1:0);
		else weekCnt = dayCnt/7+((weekminus>0)?2:1);
		return weekCnt;		
	}
	
	//打印万年历
	
	public static void printCal(int year){
		byte dayadd[]={0,1,-2,1,0,1,0,1,1,0,1,0,1}; //同样的，每月天数和30的差值，注意，dadadd[0]的0并没用到
		int wkpoint = getWeek(year,1,1);			//wkpoint用来指出当前日期的星期数		
		int t = 0;									//t用来作为一个标记器，解决闰年2月有29天的问题
		int bk = 0;									//bk用来记录需输空白的数目
		String week[]={"星期一","星期二","星期三","星期四","星期五","星期六","星期日"};
		for(int i=1;i<13;i++)
		{
			t = 0;
			bk = 0;
			if((i==2)&&(isLeap(year)==1)) 
				t = 1;								//当且仅当闰年的2月份才将其置为1
			System.out.println("\n\n\t\t"+year+" 年 "+i+" 月\n");
			for(int j=0;j<7;j++)
				System.out.print(week[j]+"\t");
			System.out.println();
			while(bk++<wkpoint)
				System.out.print('\t');
			for(int j=1;j<=(30+dayadd[i]+t);j++)
			{
				System.out.print(j+"\t");			//循环输出每月日期
				if(wkpoint==6) 
					{ wkpoint = 0; System.out.print('\n');}  //当wkpoint计数器为6时将其置为0，并换行
				else
					wkpoint++;												
			}
		}
	}
	
	public static void main(String[] args){
		String week[]={"星期一","星期二","星期三","星期四","星期五","星期六","星期日"};
		System.out.println("输入的日期是该年的第"+cptDay(2009,2,15)+"天");
		System.out.println("这一天是该年的第"+weekCount(2009,2,15)+"周 "+week[getWeek(2009,2,15)]);
		printCal(2009);
	}
}