**6.33 (Current date and time) Invoking System.currentTimeMillis() returns the
elapsed time in milliseconds since midnight of January 1, 1970. Write a program
that displays the date and time. Here is a sample run:
Current date and time is May 16, 2012 10:34:23
public class ProgrammingExercise6_33 { public static void main(String[] args) { // Obtain the total milliseconds since midnight, Jan 1, 1970 long totalMilliseconds = System.currentTimeMillis(); // Obtain the total seconds since midnight, Jan 1, 1970 long totalSeconds = totalMilliseconds / 1000; // Compute the current second in the minute in the hour long currentSecond = totalSeconds % 60; // Obtain the total minutes long totalMinutes = totalSeconds / 60; // Compute the current minute in the hour long currentMinute = totalMinutes % 60; // Obtain the total hours long totalHours = totalMinutes / 60; // Compute the current hour long currentHour = totalHours % 24; // Display results System.out.println("Current date and time is " +getDate(totalHours) +" " + currentHour + ":" + currentMinute + ":" + currentSecond + " GMT"); } public static String getDate(long numberOfHour) { String date; // Compute number of days long numberOfDay = numberOfHour / 24; int startYear = 1970; int dayReduction = 0; while (numberOfDay > 0) { if (isLeapYear(startYear)) { dayReduction = 366; numberOfDay -= 366; } else { dayReduction = 365; numberOfDay -= 365; } startYear++; } // dial it back the year and the numberOfDay back one notch numberOfDay += dayReduction; startYear--; return getMonthAndDay(numberOfDay, startYear) + " " + startYear; } public static String getMonthAndDay(long numberOfDays, int year) { int dayReduction = 0; int month; for (month = 1; month <= 12; month++) { dayReduction = getNumberOfDaysInMonth(year, month); numberOfDays -= dayReduction; if (numberOfDays < 0) break; } numberOfDays += dayReduction; return getMonthName(month) + numberOfDays+ ","; } /** 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; if (month == 4 || month == 6 || month == 9 || month == 11) return 30; if (month == 2) return isLeapYear(year) ? 29 : 28; return 0; // If month is incorrect } /** Determine if it is a leap year */ public static boolean isLeapYear(int year) { return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0); } /** 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"; } return monthName; } }
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