输入年份，然后打印出该年的万年历，以及标识出当天日期。类似于linux下的cal -y结果。

public class Permanent {

public static boolean isLeapYear(int year){//能被4整除但不能被100整除，或者能被400整除

boolean leapYear = false;

if((year % 100 == 0 && year % 400 == 0)||(year % 100 != 0 && year % 4 == 0)){

leapYear = true;

}

return leapYear;

}

public static int countDays(int year){//选个基准2015年1月1日，星期四

int countDays = 0;

int beginYear =year > 2015 ? 2015 : year;

int endYear = year > 2015 ? year : 2015;

for(int i = beginYear;i < endYear;i++ ){

if(isLeapYear(i)){

countDays += 366;

}else{

countDays += 365;

}

}

return countDays;

}

public static void showCaledar(int year){

int days = countDays(year);

int weekDay = days % 7;

if(year > 2015){

weekDay = (weekDay + 4) % 7;

}else{

weekDay = (11 -weekDay) % 7;

}

String[] monthLabels = new String[]{"January","February","March","April","May","June","July","August","September","October","November","December"};

String[] weekLabels = new String[]{"Sun","Mon","Tur","Wen","Thr","Fra","Sat"};

int[] monthDay = {31,28,31,30,31,30,31,31,30,31,30,31};

for(int i = 0;i < 12;i++){

System.out.println("\n"+monthLabels[i]);

for(String weekLabel : weekLabels){ //每一周的标签

System.out.print(weekLabel + " ");

}

System.out.println(); //下一行

for(int j = 0; j < weekDay; j++){//找到第一个日期

System.out.print(" ");

}

if(isLeapYear(year)){

monthDay[1] = 29;

}else{

monthDay[1] = 28;

}

for(int k = 1;k <= monthDay[i];k++){

if((k + weekDay - 1) % 7 == 0){

System.out.println();

}

if(k < 10){ //这里是对齐的问题

System.out.print(k + " ");

}else{

System.out.print(k + " ");

}

}

weekDay = (weekDay + monthDay[i]) % 7;

}

}

public static void main(String[] args) {

showCaledar(2014);

}

}