Date & Student

import java.util.Arrays;

public class DateAndStudent {

    static class Date {
        int day;
        int month;
        int year;

        public Date() {
            this.day = 0;
            this.month = 0;
            this.year = 0;
        }

        public Date(int day, int month, int year) {
            boolean isDateValid = true;
            if (isDayValid(day, month, year) && isMonthValid(day, month, year) && isYearValid(day, month, year)) {
                this.day = day;
                this.month = month;
                this.year = year;
            } else {
                this.day = 0;
                this.month = 0;
                this.year = 0;
            }
        }

        private boolean isYearValid(int day, int month, int year) {
            return year >= 0;
        }

        private boolean isMonthValid(int day, int month, int year) {
            return month >= 1 && month <= 12;
        }

        private boolean isDayValid(int day, int month, int year) {
            boolean result = false;
            switch (month) {
                case 1:
                case 3:
                case 5:
                case 7:
                case 8:
                case 10:
                case 12: {
                    if (day >= 1 && day <= 31) {
                        result = true;
                    }
                    break;
                }
                case 4:
                case 6:
                case 9:
                case 11: {
                    if (day >= 1 && day <= 30) {
                        result = true;
                    }
                }
                break;
                case 2: {
                    if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) {
                        if (day >= 1 && day <= 29) {
                            result = true;
                        }
                    } else if (day >= 1 && day < 28) {
                        result = true;
                    }
                }
                break;
                default:
                    break;
            }

            return result;
        }

        public int getDay() {
            return day;
        }

        public int getMonth() {
            return month;
        }

        public int getYear() {
            return year;
        }

        private static boolean isGreaterOrEqual(Date date1, Date date2) {
            return isGreater(date1, date2) || areEqual(date1, date2);
        }

        public static boolean isGreater(Date date1, Date date2) {
            if (date1.getYear() > date2.getYear()) {
                return false;
            } else if (date1.getYear() < date2.getYear()) {
                return true;
            } else {
                if (date1.getMonth() > date2.getMonth()) {
                    return false;
                } else if (date1.getMonth() < date2.getMonth()) {
                    return true;
                } else {
                    if (date1.getDay() > date2.getDay()) {
                        return false;
                    } else return date1.getDay() < date2.getDay();
                }
            }
        }

        private static boolean areEqual(Date date1, Date date2) {
            boolean result = false;
            if (date1.getDay() == date2.getDay() && date1.getMonth() == date2.getMonth()
                    && date1.getYear() == date2.getYear()) {
                result = true;
            }

            return result;
        }


    }


    static class Student {
        char[] name;
        Date birthDate;

        public Student() {
            name = new char[]{};
            this.birthDate = new Date(1, 1, 2017);
        }

        public Student(char[] name, Date dateOfBirth) {
            this.name = name;
            this.birthDate = dateOfBirth;
        }

        private char[] getName() {
            return name;
        }

        public Date getBirthDate() {
            return birthDate;
        }

        private static boolean isBefore(Student student1, Student student2) {
            char[] firstName = student1.getName();
            char[] secondName = student2.getName();

            int length1 = firstName.length;
            int length2 = secondName.length;
            int minLength = Math.min(length1, length2);

            for (int i = 0; i < minLength; i++) {
                char firstNameChar = firstName[i];
                char secondNameChar = secondName[i];
                if (firstNameChar != secondNameChar) {
                    return firstNameChar > secondNameChar;
                }
            }

            if (length1 != length2) {
                return length1 > length2;
            } else {
                return isGreater(student1.getBirthDate(), student2.getBirthDate());
            }
        }

    }

    public static boolean isGreater(Date date1, Date date2) {
        if (date1.getYear() > date2.getYear()) {
            return false;
        } else if (date1.getYear() < date2.getYear()) {
            return true;
        } else {
            if (date1.getMonth() > date2.getMonth()) {
                return false;
            } else if (date1.getMonth() < date2.getMonth()) {
                return true;
            } else {
                if (date1.getDay() > date2.getDay()) {
                    return false;
                } else return date1.getDay() < date2.getDay();
            }
        }
    }

}