Selina Day of the year

Main.java

import java.io.IOException;
import java.util.Scanner;

public class Main {
    /**
     * @param year a year greater or equal to 1900
     * @return whether that year was a leap year
     */
    static boolean isLeapYear(int year) {
        // ...
        boolean LeapYear = false;
        if (year % 4 == 0) {
            LeapYear = true;
        }
        if (year % 100 == 0) {
            LeapYear = false;
        } 
        if (year % 400 == 0) {
            LeapYear = true;
        } 
        return LeapYear;
    }

    /**
     * @param month a month between 1 and 12
     * @param year  a year greater or equal than 1900
     * @return number of days in the month of that year
     */
    static int countDaysInMonth(int month, int year) {

        int number_Of_DaysInMonth = 0;
        boolean LeapYear = isLeapYear(year);
        switch (month) {
        case 1:
            // MonthOfName = "January";
            number_Of_DaysInMonth = 31;
            break;
        case 2:
            // MonthOfName = "February";
            if (LeapYear == true) {
                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;

        }
        return number_Of_DaysInMonth;
    }

    /**
     * @param day   a day between 1 and 31
     * @param month a month between 1 and 12
     * @param year  a year greater or equal than 1900
     * @return whether the date is valid
     */

    static boolean isValidDate(int day, int month, int year) {
        if (day < 1 || day > 31)
            return false;

        if (month < 1 || month > 12)
            return false;

        if (year < 1900)
            return false;

        if (day > countDaysInMonth(month, year))
            return false;

        return true;
    }

    /**
     * (the given values should represent a valid date)
     * 
     * @param day   a day between 1 and 31
     * @param month a month between 1 and 12
     * @param year  a year greater or equal than 1900
     * @return number of days between Monday January 1, 1900 and this date
     */
    static int countDays(int day, int month, int year) {
        int countTotalLeapYears = 0;
        int countDaysInFullMonth = 0;
        for (int i = 1900; i < year; i++) {
            if (isLeapYear(i) == true) {
                countTotalLeapYears += 1;
            }
        }
        for (int i = 1; i < month; i++) {
            countDaysInFullMonth += countDaysInMonth(i, year);
        }

        int TotalDays = 0;
        TotalDays = (year - 1900) * 365 + countTotalLeapYears + countDaysInFullMonth + day;
        return TotalDays;
    }

    public static void main(String[] args) throws IOException{

        Scanner input = new Scanner(System.in);
        System.out.print("Enter a day between 1 and 31 \n");
        int day = input.nextInt();
        System.out.println("Enter a month between 1 and 12\n");
        int month = input.nextInt();
        System.out.println("Enter a year greater or equal than 1900\n");
        int year = input.nextInt();

        boolean isValid = isValidDate(day, month, year);
        assert isValid : "Date not valid";

        int TotalDays = countDays(day, month, year);

        if (TotalDays % 7 == 0) {
            System.out.print("sunday");
        } else if (TotalDays % 7 == 1) {
            System.out.print("monday");
        } else if (TotalDays % 7 == 2) {
            System.out.print("tuesday");
        } else if (TotalDays % 7 == 3) {
            System.out.print("wednesday");
        } else if (TotalDays % 7 == 4) {
            System.out.print("thursday");
        } else if (TotalDays % 7 == 5) {
            System.out.print("friday");
        } else {
            System.out.print("saturday");
        }
    }
}

SelinaVersion.java

public class Main {
  /**
   * @param year   a year greater or equal to 1900
   * @return       whether that year was a leap year
   */
  static boolean isLeapYear(int year) {
    // ...
    boolean LeapYear = false;
    if (year%4 != 0 ){
      LeapYear = false;
    } else if (year%100 != 0) {
      LeapYear = true;
    } else if (year%400 != 0) {
      LeapYear = false;
    } else {
      LeapYear = true;
    }
    return LeapYear;
  }
 

  /**
   * @param month  a month between 1 and 12
   * @param year   a year greater or equal than 1900
   * @return       number of days in the month of that year
   */
  static int countDaysInMonth(int month, int year) {

    int number_Of_DaysInMonth = 0;
    boolean LeapYear = isLeapYear(year);
    switch (month) {
            case 1:
                //MonthOfName = "January";
                number_Of_DaysInMonth = 31;
                break;
            case 2:
                //MonthOfName = "February";
                if (LeapYear==true) {
                    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;
  

  }
    return number_Of_DaysInMonth;
}

  /**
   * @param day    a day between 1 and 31
   * @param month  a month between 1 and 12
   * @param year   a year greater or equal than 1900
   * @return       whether the date is valid
   */
   
  static boolean isValidDate(int day, int month, int year) {
    /*assert day >= 1 && day <= 31 : "Invalid date";
    
    assert month >= 1 && month <= 12 : "Invalid date";
    
    assert year >= 1900 : "Invalid date";
    
    assert isLeapYear(year) == false && month == 2 && day > 29 : "Invalid date";
    
    return true;*/
    boolean Valid = false;
    if (isLeapYear(year)==false && month == 2 && day > 28){
      Out.print("invalid date");
      Valid = false;
    } else if (day >= 1 && day <= 31 && month >= 1 && month <= 12 && year >= 1900) {
      Out.print("invalid date");
      Valid = true;
    }
    return Valid;
    
    /*if (day >= 1 && day <= 31 && month >= 1 && month <= 12 && year >= 1900 || isLeapYear(year) == false && month == 2 && day < 29){
      return true;
    } else {
      Out.print("invalid date");
      return false;
    }*/
  }
   


  /**
   * (the given values should represent a valid date)
   * @param day    a day between 1 and 31
   * @param month  a month between 1 and 12
   * @param year   a year greater or equal than 1900
   * @return       number of days between Monday January 1, 1900 and this date
   */
  static int countDays(int day, int month, int year) {
    int countTotalLeapYears = 0;
    int countDaysInFullMonth = 0;
    for (int i = 1900; i<year; i++){
      if (isLeapYear(i)==true){
        countTotalLeapYears += 1;
      }
    }
    for (int i=1; i<month; i++){
      countDaysInFullMonth += countDaysInMonth(i, year);
    }
    
    int TotalDays = 0;
    if (year > 1901){
      TotalDays = (year - 1901) * 365 + countTotalLeapYears + countDaysInFullMonth + day;
    } else if (year == 1901){
      TotalDays = 365 + countDaysInFullMonth + day;
    } else {
      TotalDays = countDaysInFullMonth + day;
    }
    
    return TotalDays;
  }

  public static void main(String[] args) {
    
    //Out.print("Enter a day between 1 and 31");
    int day = In.readInt();
    //Out.println("Enter a month between 1 and 12");
    int month = In.readInt();
    //Out.println("Enter a year greater or equal than 1900");
    int year = In.readInt();
    
    boolean isValid = isValidDate( day, month, year );
    boolean LeapYear = isLeapYear(year);

    
    
    int TotalDays = countDays(day, month, year);
    
    if (TotalDays%7 == 0){
      Out.print("sunday");
    } else if (TotalDays%7 == 1){
      Out.print("monday");
    } else if (TotalDays%7 == 2){
      Out.print("tuesday");
    } else if (TotalDays%7 == 3){
      Out.print("wednesday");
    } else if (TotalDays%7 == 4){
      Out.print("thursday");
    } else if (TotalDays%7 == 5){
      Out.print("friday");
    } else {
      Out.print("saturday");
    }
    
    
    
   // Out.print("Enter a number: ");
  //  int n = In.readInt();
   // boolean is2019LeapYear = isLeapYear(2000);
    //Out.print(is2019LeapYear);
  }
}

static boolean isLeapYear(int year) {
    // ...
    boolean LeapYear = false;
    if (year%4 != 0 ){
      LeapYear = false;
    } else if (year%100 != 0) {
      LeapYear = true;
    } else if (year%400 != 0) {
      LeapYear = false;
    } else {
      LeapYear = true;
    }
    return LeapYear;
 }

Do isch s problem, das de bi dr erscht if condition duesch luege öbs niid durch 4 Teilbar isch if (year%4 != 0 ). Das sin alli johr wo kei schaltjohr sin und denne setzisch diä uf true. Dadurch das de nochher else if und else nimmsch springt er us em ganze if block use und het somit alli Schaltjoohr verchert gha. Ih han das abgändert in das:

static boolean isLeapYear(int year) {
        // ...
        boolean LeapYear = false;
        if (year % 4 == 0) {
            LeapYear = true;
        }
        if (year % 100 == 0) {
            LeapYear = false;
        } 
        if (year % 400 == 0) {
            LeapYear = true;
        } 
        return LeapYear;
}

zweiti Funktion static int countDaysInMonth(int month, int year) isch perfekt super 💯 🥇

bi is valid date wär dini funktion mit de assert au fascht richtig gsi:
s einzig wo falsch gsi isch isch das

assert isLeapYear(year) == false && month == 2 && day > 29 : "Invalid date";

Bi assert muesch immer luege das diä ganzi kondition true isch sunscht bricht s program ab. Do wär er bi jedem Datum wo nid es Schaltjoohr isch und bi jedem Datum wo niid im Februar isch abbroche worde.

Was de guet überleggt hesch isch das de muesch im Februar luege das er niid dörf grösser als 29 si. Aber das muesch au luege wenn er kei Schaltjoohr isch und au bi allne ander Mönet wo nume 30 täg hän.

Ih han das mit dinere Perfekt Funktion countDaysInMonth(month, year) 💯 glöst

if (day > countDaysInMonth(month, year))
            return false;

und diä ganz funktion hani no es bitzeli umgschribe das si chliih übersichtlichter isch

    static boolean isValidDate(int day, int month, int year) {
        if (day < 1 || day > 31)
            return false;

        if (month < 1 || month > 12)
            return false;

        if (year < 1900)
            return false;

        if (day > countDaysInMonth(month, year))
            return false;

        return true;
    }

bi de static int countDays(int day, int month, int year) isch au wieder fascht alles richtig gsi 👍 bzw. si würdi funktioniere 💯
Jedoch bruchts diä ganze if am schluss nid

if (year > 1901){
      TotalDays = (year - 1901) * 365 + countTotalLeapYears + countDaysInFullMonth + day;
    } else if (year == 1901){
      TotalDays = 365 + countDaysInFullMonth + day;
    } else {
      TotalDays = countDaysInFullMonth + day;
    }

chame eifach schribe als

TotalDays = (year - 1900) * 365 + countTotalLeapYears + countDaysInFullMonth + day;

im public static void main(String[] args)
isch wieder alles tiptop gsi 💯

Im gross ganze super gsi nur es paar chleini fehlerli gmacht. Wiiter so 👍

Ehm ih hans halt alli Outund In miesse in System.out und System.in miesse umwandle das muesch wieder zruggwandle. Sorry