CODEWITHSUNDEEP
javagregorian-calendarleap-year
Francis
Francis

Reputation: 29

How to Print the next 20 leap years in Java

I was wondering how to do this because of my assignment.

package leapyearsassignment;

import java.util.Scanner;

public class LeapYearsAssignment {
    public static void main(String[] args) {
        int leapyear;
        int addyear = 4;
        int year;
        Scanner in = new Scanner(System.in);

        System.out.println("Please enter a year to print the next 20 years.");
        year = in.nextInt();
        System.out.println( "You are asking for the leap years starting from " + year + ".");

        //for loop here?

    }

}

This is what I started with wondering how I would be able to put a 'for loop' to print the next 20 leap years from the year what the user wanted.

EDIT: This is the code I've made before:

package leapyearsassignment;

public class LeapYearsAssignment {


    public static void main(String[] args) {
        int year;

        for ( year = 2016; year <= 2092; year = year +4) {
            System.out.println(year);}

    }

}

But instead of 2016, I want the year the user wanted.I'm fairly new to programming and just started a few months ago; September to be exact.

Upvotes: 1

Views: 7912

Answers (5)

Basil Bourque
Basil Bourque

Reputation: 339669

tl;dr

Year.now().plusYears( n ).isLeap()

java.time.Year

Use the modern java.time classes defined in JSR 310, built into Java 8+. Specifically, Year.

Get the year for an int integer number provided by the user.

Year startYear = Year.of( y ) ;

Alternatively, default to the current year. That requires a time zone. For any given moment, the date varies around the globe by time zone. Around the last/first day of the year, the year can vary by time zone. For example “next year” in Tokyo Japan can be simultaneously “last year” in Toledo Ohio US.

ZoneId z = ZoneId.of( "America/Edmonton" ) ;
Year startYear = Year.now( z ) ;

Loop for twenty years. Test each year with Year#isLeap.

for ( int index = 0 ; index < 20 ; index ++ )
{
    Year year = startYear.plusYears( index ) ; 
    if ( year.isLeap() ) System.out.println( year ) ;
}

Or, using streams.

LocalDate today = LocalDate.now( z ) ;
today
    .datesUntil( today.plusYears( 20 ) , Period.ofYears ( 1 ) )
    .map( Year :: from )
    .filter( Year :: isLeap )
    .forEach( System.out :: println ) ;

See this code run at Ideone.com.

2024
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2040

Upvotes: 1

Pradwin Sherigar
Pradwin Sherigar

Reputation: 1

    Scanner sc = new Scanner(System.in);
    System.out.println("Enter the year to check for leap year.");
    int year = sc.nextInt();

    System.out.println("The next 20 leap years from the given year " + year+ " are: ");
    int count =0;
    while(count != 20){
    year++;
    if((year%400==0) || (year%4==0 && year%100 != 0)){
        System.out.println(year);
        count++;
    }
    }
    sc.close();

Upvotes: 0

Rajdeep Dodia
Rajdeep Dodia

Reputation: 11

Scanner in = new Scanner(System.in);
int count =  0;

System.out.println("Enter a year");
int current_year = in.nextInt();
System.out.println("The next 20 leap years from "+current_year+" are ");

while(count < 20){
    
    if((current_year % 4 == 0) && (current_year % 100 != 0) || (current_year % 400 == 0))
    {
        System.out.print(current_year+", ");
        count++;
    }
    current_year++;
    
}

Upvotes: 1

Durandal
Durandal

Reputation: 20069

One way to do this (accounting correctly for the irregular leap years) is:

  • Use a counter variable to count the number of leap years printed
  • In a loop:
    • Test if year is a leap year
      • If it is a leap year, increment the counter and print the year
      • If the counter reaches 20, break the loop
      • Otherwise, increment year and continue looping

To determine if year is a leap year, you can use this method:

public static boolean isLearYear(int year) {
    return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
}

(This checks that the year is divisible by 4, and accounts for the special exceptions that every 100th year is not a leap year, but every 400th is a leap year again).

Upvotes: 0

Rudra Rokaya
Rudra Rokaya

Reputation: 685

Scanner sc = new Scanner(System.in);
    System.out.println("Enter the year to check for leap year.");
    int year = sc.nextInt();

    System.out.println("The next 20 leap years from the given year " + year+ " are: ");
    int count =0;
    while(count != 20){
    year = year+4;
    if((year%400==0) || (year%4==0 && year%100 != 0)){
        System.out.println(year);
    }
    count++;
    }

Upvotes: 1

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