How to find day before N years in Java?

Problem Description :

Write a program in Java that finds a day before N years. For example - on 25th Jan 2017 day is Wednesday and 7 years ago on same date 25th Jan 2010 day was Monday.

A day before n years in Java

Concept :

The solution of this problem is very simple. With the help of Calendar class constant YEAR and DAY_OF_WEEK we can easily solve this problem.

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Java Program :

	package com.javamultiplex.datetime;
	import java.text.DateFormat;
	import java.text.SimpleDateFormat;
	import java.util.Calendar;
	import java.util.Date;
	import java.util.Scanner;
	/**
	*
	* @author Rohit Agarwal
	* @category Date and Time Problems
	* @problem Day before N years?
	*
	*/
	public class DayBeforeNYears {
	public static void main(String[] args) {
	Scanner input = null;
	try {
	input = new Scanner(System.in);
	System.out.println("Enter number of years : ");
	int years = input.nextInt();
	// Creating Calendar class instance
	Calendar calendar = Calendar.getInstance();
	String currentDate = getStringFromCalendar(calendar);
	int dayofWeek = calendar.get(Calendar.DAY_OF_WEEK);
	String dayName = getDayName(dayofWeek);
	System.out.println("Current Date (dd/MM/yyyy) :" + currentDate + " and Day :" + dayName);
	// Subtracting years from Calendar.
	calendar.add(Calendar.YEAR, -years);
	String newDate = getStringFromCalendar(calendar);
	dayofWeek = calendar.get(Calendar.DAY_OF_WEEK);
	dayName = getDayName(dayofWeek);
	System.out.println("Before " + years + " year/s Date (dd/MM/yyyy) :" + newDate + " and Day :" + dayName);
	} finally {
	if (input != null) {
	input.close();
	}
	}
	}
	private static String getDayName(int dayofWeek) {
	String dayName = null;
	switch (dayofWeek) {
	case 1:
	dayName = "Sunday";
	break;
	case 2:
	dayName = "Monday";
	break;
	case 3:
	dayName = "Tuesday";
	break;
	case 4:
	dayName = "Wednesday";
	break;
	case 5:
	dayName = "Thursday";
	break;
	case 6:
	dayName = "Friday";
	break;
	case 7:
	dayName = "Saturday";
	break;
	}
	return dayName;
	}
	private static String getStringFromCalendar(Calendar calendar) {
	// Converting Calendar to Date.
	Date currentDate = calendar.getTime();
	DateFormat format = new SimpleDateFormat("dd/MM/yyyy");
	// Converting Date to String.
	String myCurrentDate = format.format(currentDate);
	return myCurrentDate;
	}
	}

view raw DayBeforeNYears.java hosted with ❤ by GitHub

Output :

Output - How to find a day before N years in Java?

References :

https://docs.oracle.com/javase/7/docs/api/java/util/Date.html

https://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html

https://docs.oracle.com/javase/7/docs/api/java/lang/String.html

Thank you friends, I hope you have clearly understood the solution of this problem. If you have any doubt, suggestion or query please feel free to comment below. You can also discuss this solution in our forum.

Tags : Date and Time problems, Day before n years, Solution in Java, DateFormat, SimpleDateFormat, String, Calendar, switch statement.

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