Code for java.util.Calendar

If you have to use java.util.Calendar, I suspect you want:

int days = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

Code for Joda Time

Personally, however, I'd suggest using Joda Time instead of java.util.{Calendar, Date} to start with, in which case you could use:

int days = chronology.dayOfMonth().getMaximumValue(date);

Note that rather than parsing the string values individually, it would be better to get whichever date/time API you're using to parse it. In java.util.* you might use SimpleDateFormat; in Joda Time you'd use a DateTimeFormatter.

You can use Calendar.getActualMaximum method:

Calendar calendar = Calendar.getInstance();

calendar.set(Calendar.YEAR, year);

calendar.set(Calendar.MONTH, month);

int numDays = calendar.getActualMaximum(Calendar.DATE);

java.time.LocalDate

From Java 1.8, you can use the method lengthOfMonth on java.time.LocalDate:

LocalDate date = LocalDate.of(2010, 1, 19);

int days = date.lengthOfMonth();

if (month == 4 || month == 6 || month == 9 || month == 11)



daysInMonth = 30;



else 



if (month == 2) 



daysInMonth = (leapYear) ? 29 : 28;



else 



daysInMonth = 31;

This is the mathematical way:

For year, month (1 to 12):

int daysInMonth = month == 2 ? 

    28 + (year % 4 == 0 ? 1:0) - (year % 100 == 0 ? (year % 400 == 0 ? 0 : 1) : 0) :

    31 - (month-1) % 7 % 2;

In Java8 you can use get ValueRange from a field of a date.

LocalDateTime dateTime = LocalDateTime.now();



ChronoField chronoField = ChronoField.MONTH_OF_YEAR;

long max = dateTime.range(chronoField).getMaximum();

This allows you to parameterize on the field.

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;



/*

 * 44. Return the number of days in a month

 * , where month and year are given as input.

 */

public class ex44 {

    public static void dateReturn(int m,int y)

    {

        int m1=m;

        int y1=y;

        String str=" "+ m1+"-"+y1;

        System.out.println(str);

        SimpleDateFormat sd=new SimpleDateFormat("MM-yyyy");



        try {

            Date d=sd.parse(str);

            System.out.println(d);

            Calendar c=Calendar.getInstance();

            c.setTime(d);

            System.out.println(c.getActualMaximum(Calendar.DAY_OF_MONTH));

        } catch (ParseException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }



    }

    public static void main(String args) {

dateReturn(2,2012);





    }



}

    String date = "11-02-2000";

    String input = date.split("-");

    int day = Integer.valueOf(input[0]);

    int month = Integer.valueOf(input[1]);

    int year = Integer.valueOf(input[2]);

    Calendar cal=Calendar.getInstance();

    cal.set(Calendar.YEAR,year);

    cal.set(Calendar.MONTH,month-1);

    cal.set(Calendar.DATE, day);

    //since month number starts from 0 (i.e jan 0, feb 1), 

    //we are subtracting original month by 1

    int days = cal.getActualMaximum(Calendar.DAY_OF_MONTH);

    System.out.println(days);

Following method will provide you the no of days in a particular month

public static int getNoOfDaysInAMonth(String date) {



        Calendar cal = Calendar.getInstance();

        cal.setTime(date);

        return (cal.getActualMaximum(Calendar.DATE));

    }

You can use Calendar.getActualMaximum method:

    Calendar calendar = Calendar.getInstance();

    calendar.set(Calendar.YEAR, year);

    calendar.set(Calendar.MONTH, month-1);

    int numDays = calendar.getActualMaximum(Calendar.DATE);

And month-1 is Because of month takes its original number of month while in method takes argument as below in Calendar.class

   public int getActualMaximum(int field) {

      throw new RuntimeException("Stub!");

   }

And the (int field) is like as below.

    public static final int JANUARY = 0;

    public static final int NOVEMBER = 10;

    public static final int DECEMBER = 11;

This worked fine for me.

This is a Sample Output

import java.util.*;



public class DaysInMonth{ 



public static void main(String args ){ 



Scanner input = new Scanner(System.in); 

System.out.print("Enter a year:"); 



int year = input.nextInt(); //Moved here to get input after the question is asked 



System.out.print("Enter a month:"); 

int month = input.nextInt(); //Moved here to get input after the question is asked 



int days = 0; //changed so that it just initializes the variable to zero

boolean isLeapYear = (year % 4 == 0 && year % 100 != 0)||(year % 400 == 0); 



switch (month){ 

case 1: 

days = 31; 

break; 

case 2: 

if (isLeapYear) 

days = 29; 

else 

days = 28; 

break; 

case 3: 

days = 31; 

break; 

case 4: 

days = 30; 

break; 

case 5: 

days = 31; 

break; 

case 6: 

days = 30; 

break; 

case 7: 

days = 31; 

break; 

case 8: 

days = 31; 

break; 

case 9: 

days = 30; 

break; 

case 10: 

days = 31; 

break; 

case 11: 

days = 30; 

break; 

case 12: 

days = 31; 

break; 

default: 

String response = "Have a Look at what you've done and try again";

System.out.println(response); 

System.exit(0); 

} 

String response = "There are " +days+ " Days in Month "+month+ " of Year " +year+ ".n"; 

System.out.println(response); // new line to show the result to the screen. 

} 

} //abhinavsthakur00@gmail.com

public class Main {



    private static LocalDate local=LocalDate.now();

    public static void main(String args) {



            int month=local.lengthOfMonth();

            System.out.println(month);



    }

}

The use of outdated Calendar API should be avoided.

In Java8 or higher version, this can be done with YearMonth.

Example code:

int year = 2011;

int month = 2;

YearMonth yearMonth = YearMonth.of(year, month);

int lengthOfMonth = yearMonth.lengthOfMonth();

System.out.println(lengthOfMonth);

Simple as that,no need to import anything

public static int getMonthDays(int month, int year) {

    int daysInMonth ;

    if (month == 4 || month == 6 || month == 9 || month == 11) {

        daysInMonth = 30;

    }

    else {

        if (month == 2) {

            daysInMonth = (year % 4 == 0) ? 29 : 28;

        } else {

            daysInMonth = 31;

        }

    }

    return daysInMonth;

}

String  MonthOfName = "";

int number_Of_DaysInMonth = 0;



//year,month

numberOfMonth(2018,11); // calling this method to assign values to the variables MonthOfName and number_Of_DaysInMonth 



System.out.print("Number Of Days: "+number_Of_DaysInMonth+"   name of the month: "+  MonthOfName );



public void numberOfMonth(int year, int month) {

    switch (month) {

        case 1:

            MonthOfName = "January";

            number_Of_DaysInMonth = 31;

            break;

        case 2:

            MonthOfName = "February";

            if ((year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0))) {

                number_Of_DaysInMonth = 29;

            } else {

                number_Of_DaysInMonth = 28;

            }

            break;

        case 3:

            MonthOfName = "March";

            number_Of_DaysInMonth = 31;

            break;

        case 4:

            MonthOfName = "April";

            number_Of_DaysInMonth = 30;

            break;

        case 5:

            MonthOfName = "May";

            number_Of_DaysInMonth = 31;

            break;

        case 6:

            MonthOfName = "June";

            number_Of_DaysInMonth = 30;

            break;

        case 7:

            MonthOfName = "July";

            number_Of_DaysInMonth = 31;

            break;

        case 8:

            MonthOfName = "August";

            number_Of_DaysInMonth = 31;

            break;

        case 9:

            MonthOfName = "September";

            number_Of_DaysInMonth = 30;

            break;

        case 10:

            MonthOfName = "October";

            number_Of_DaysInMonth = 31;

            break;

        case 11:

            MonthOfName = "November";

            number_Of_DaysInMonth = 30;

            break;

        case 12:

            MonthOfName = "December";

            number_Of_DaysInMonth = 31;

    }

}