I'm getting NumberFormatException. How to solve it.

Question about the task

Working with dates

Java Syntax, Level 8, Lesson 11

Resolved

where i'm wrong, please help.

1. Implement the isDateOdd(String date) method so that it returns true if the number of days since the beginning of the year is odd, and otherwise returns false
2. String date is passed in the form: FEBRUARY 1 2013
Don't forget to account for the first day of the year.

Example:
JANUARY 1 2000 = true JANUARY 2 2020 = false

Requirements:

The program should display text on the screen.
The Solution class must have two methods.
The isDateOdd() method must return true if the number of days since the beginning of the year is odd, and must otherwise return false.
The main() method should call the isDateOdd() method.

package com.codegym.task.task08.task0827; import java.util.Date; import java.util.Arrays; /* Working with dates */ public class Solution { public static void main(String[] args) { long days[] = {31,28,31,30,31,30,31,30,31,30,31,30}; System.out.println(isDateOdd("MAY 1 2013")); } public static boolean isDateOdd(String date) { int month = Integer.parseInt(date.substring(0,4)); int day = Integer.parseInt(date.substring(5,7)); int year = Integer.parseInt(date.substring(8)); int days[] = {31,28,31,30,31,30,31,30,31,30,31,30}; if(month > 2 && year % 4 == 0 &&(year%100 != 0 || year%400 == 0)){ ++day; } while(--month > 0){ day += days[month-1]; } if(day % 2 == 0) { return true; } else { return false; } } }

Comments (5)

Popular
New
Old

You must be signed in to leave a comment

Mayu

Level 25 , Toronto, Canada

29 June 2020, 16:52

I learnt about calendars after solving this problem, I used instead the SimpleDateFormat from java.text , which you can use to read in the date from the isDateOdd parameter. The parameter format "January 1 2020" would be "MMMMM d yyyy". http://javatechniques.com/blog/dateformat-and-simpledateformat-examples/ this website should help.

Thomas

Level 41 , Bayreuth, Germany

29 June 2020, 08:56

MAY isn't a number. If you try parse it in line 18 you get that exception. You'd need to create a Sting array with the month names, the index of the months name is the numeric representation. Then compare the substring with the arry and find out the number. The easiest way to solve this task is to use a Calendar object (getInstance()). That Calendar object you can initialize with a Date object via the setTime() method. The setTime method takes a Date object. Give the Date objects constructor the date you need to parse (eg. FEBRUARY 1 2013). Calendar has some static variables you can access using get, like Calendar.DAY_OF_YEAR. This is what you need. The number of the day in the year of the date you passed to the calendar.

Tata

Level 16 , Hisar, Haryana, India

30 June 2020, 05:53

could you please tell me, now where I am wrong😭😭

import java.util.Date;
import java.util.Calendar;
import java.util.*;
/*
Working with dates

*/

public class Solution {
    public static void main(String[] args) {
        System.out.println(isDateOdd("MAY 1 2013"));
    }

    public static boolean isDateOdd(String date) {
        Date input = new Date(date);

        Calendar calendar = Calendar.getInstance(calendar.DAY_OF_YEAR);
        //int day = calendar.DAY_OF_YEAR;
        calendar.setTime(input);

        return true;
    }
}

Thomas

Level 41 , Bayreuth, Germany

30 June 2020, 06:07

getInstance(); this just should create a new Calendar. With setTime you gave it a data (today), this command is OK. Now you can use int time = calendar.get(Calendar.DAY_OF_YEAR);

Tata

Level 16 , Hisar, Haryana, India

30 June 2020, 10:59

Thanks brother.😊😊