chapter_12_beginning_javabook

Get calendardayofmonth currentsystemdateget

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Unformatted text preview: gorianCalendar ; class CurrentDate extends Date { public CurrentDate() { Calendar current_system_date this_day this_month this_year = = = = new GregorianCalendar() ; current_system_date.get( Calendar.DAY_OF_MONTH ) ; current_system_date.get( Calendar.MONTH ) + 1 ; current_system_date.get( Calendar.YEAR ) ; date_print_format = 'A' ; } public CurrentDate( char given_date_print_format ) { this() ; date_print_format = given_date_print_format ; } } The second constructor of class CurrentDate first calls the first constructor with the help of the this keyword, and then sets the date_print_format to the given When you compile programs which use the value. CurrentDate class (e.g. Titanic.java and Weddingdates.java), you should have the files CurrentDate.java, Date.java, and DateDistance.java in the same folder (directory) as the file being compiled. The file DateDistance.java is always needed because Date.java cannot be compiled without it. CurrentDate.java - 1. The declaration of class CurrentDate. 12.1 Base classes and derived classes Objects of class CurrentDate are usually created without supplying any parameters to the constructor of the class. This declaration results in that the object referenced by date_of_today contains the date information that is maintained by the operating system of the computer where this program is being executed. // Titanic.java (c) Kari Laitinen class Titanic { public static void main( String not_in_use ) { Date date_when_titanic_sank = new Date( "04/15/1912" ) ; CurrentDate DateDistance date_of_today = time_from_sinking new CurrentDate() ; = date_of_today.get_distance_to( date_when_titanic_sank ) ; System.out.print( + + + + + + + "\n Today it is " + date_of_today ".\n On " + date_when_titanic_sank ", the famous ship \"Titanic\" went to" "\n the bottom of Atlantic Ocean." "\n That happened " time_from_sinking.years + " years, " time_from_sinking.months + " months, and " time_from_sinking.days + " days ago. \n\n" ) ; } } Because of inheritance, the methods of class Date can be called for CurrentDate objects. Here, for example, methods get_distance_to() and toString() are invoked for the CurrentDate object pointed by date_of_today. Titanic.java - 1. A program that uses both a Date object and a CurrentDate object. D:\javafiles3>java Titanic Today it is 03/01/2005. On 04/15/1912, the famous ship "Titanic" went to the bottom of Atlantic Ocean. That happened 92 yea...
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This document was uploaded on 01/20/2014.

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