Using Calendar.getInstance();

[Dustin Schreader]

I have this method that is supposed to display the day of week given the preferred month, day, and year. When I test this method I get the wrong day and if I try to enter a higher number for the day such as 17 I get an arrayIndexOutofBoundsException: 7. I'm using the gregorianCalendar. Am I not correctly using DAY_OF_WEEK?

    private String dayOfWeek ( int month, int day, int year)
    // Returns the day of the week corresponding to the specified day.
    {  
       calendar.set(Calendar.YEAR, year);
       calendar.set(Calendar.MONTH, month - 1);
       calendar.set(Calendar.DAY_OF_MONTH, day);
       int weekday = calendar.get(Calendar.DAY_OF_WEEK);  
      
       return wkDay[weekday];
    }
    public void displayCalendar (int month, int day, int year)
    // Displays a logbook using the traditional calendar format.
    {
      System.out.println(String.format("%28s", year));
      System.out.println(String.format("%28s", month(month)));
      System.out.println(dayOfWeek(month, day, year));
                           

    }

[Matthew Brown]

The method looks right. But that suggests that the day-of-week is 1-7. But you then use it as an array index, which needs to be 0-6.

[bhanu chowdary]

use getFirstDayOfWeek() and see what is the first day of the week. If this is not the first day according to your week then you can set it. And regarding the Exception you are maintaining an array so the indexes will be from 0 to 6, so use wkDay[weekday-1]. Constant field values for days

[Jesper de Jong]

calendar.get(Calendar.DAY_OF_WEEK) returns a number between 1 and 7, where 1 is Sunday, 2 is Monday, etc., until 7 is Saturday.

If you use that number to index into an array, you probably have to subtract 1 from it:

private final static String[] wkDay = { "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa" };

// ...

int weekday = calendar.get(Calendar.DAY_OF_WEEK);

String name = wkDay[weekday - 1];

[Dustin Schreader]

Very cool, It works now and I only had to change weekday - 1! Thank you!

[Rob Spoor]

Actually, you should subtract Calendar.SUNDAY, as that's the offset. Calendar.SUNDAY just happens to be 1, but if you use this same technique for months (with Calendar.JANUARY being 0, go figure...) you won't end up in any problems.