import java.util.Scanner;
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public class PrintCalendar {
/** Main method */
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
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// Prompt the user to enter year
System.out.print("Enter full year (e.g., 2001): ");
int year = input.nextInt();
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// Prompt the user to enter month
System.out.print("Enter month in number between 1 and 12: ");
int month = input.nextInt();
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// Print calendar for the month of the year
printMonth(year, month);
}
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/** Print the calendar for a month in a year */
public static void printMonth(int year, int month) {
// Print the headings of the calendar
printMonthTitle(year, month);
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// Print the body of the calendar
printMonthBody(year, month);
}
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/** Print the month title, e.g., May, 1999 */
public static void printMonthTitle(int year, int month) {
System.out.println(" " + getMonthName(month)
+ " " + year);
System.out.println("-----------------------------");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
}
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/** Get the English name for the month */
public static String getMonthName(int month) {
String monthName = "";
switch (month) {
case 1: monthName = "January"; break;
case 2: monthName = "February"; break;
case 3: monthName = "March"; break;
case 4: monthName = "April"; break;
case 5: monthName = "May"; break;
case 6: monthName = "June"; break;
case 7: monthName = "July"; break;
case 8: monthName = "August"; break;
case 9: monthName = "September"; break;
case 10: monthName = "October"; break;
case 11: monthName = "November"; break;
case 12: monthName = "December";
}
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return monthName;
}
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/** Print month body */
public static void printMonthBody(int year, int month) {
// Get start day of the week for the first date in the month
int startDay = getStartDay(year, month);
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// Get number of days in the month
int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);
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// Pad space before the first day of the month
int i = 0;
for (i = 0; i < startDay; i++)
System.out.print(" ");
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for (i = 1; i <= numberOfDaysInMonth; i++) {
System.out.printf("%4d", i);
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if ((i + startDay) % 7 == 0)
System.out.println();
}
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System.out.println();
}
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/** Get the start day of month/1/year */
public static int getStartDay(int year, int month) {
final int START_DAY_FOR_JAN_1_1800 = 3;
// Get total number of days from 1/1/1800 to month/1/year
int totalNumberOfDays = getTotalNumberOfDays(year, month);
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// Return the start day for month/1/year
return (totalNumberOfDays + START_DAY_FOR_JAN_1_1800) % 7;
}
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/** Get the total number of days since January 1, 1800 */
public static int getTotalNumberOfDays(int year, int month) {
int total = 0;
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// Get the total days from 1800 to 1/1/year
for (int i = 1800; i < year; i++)
if (isLeapYear(i))
total = total + 366;
else
total = total + 365;
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// Add days from Jan to the month prior to the calendar month
for (int i = 1; i < month; i++)
total = total + getNumberOfDaysInMonth(year, i);
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return total;
}
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/** Get the number of days in a month */
public static int getNumberOfDaysInMonth(int year, int month) {
if (month == 1 || month == 3 || month == 5 || month == 7 ||
month == 8 || month == 10 || month == 12)
return 31;
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if (month == 4 || month == 6 || month == 9 || month == 11)
return 30;
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if (month == 2) return isLeapYear(year) ? 29 : 28;
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return 0; // If month is incorrect
}
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/** Determine if it is a leap year */
public static boolean isLeapYear(int year) {
return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
}
}
原文：http://www.cnblogs.com/3013218061shang/p/5315584.html