Question

I'm having trouble with the daysSince() Method in bold at the end of the program

public class Date {
        static final  int [] daysInMonth = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        private int day, month, year;
        public Date() {
                day = 1;
                month = 1;
                year = 2000;
        }
        public Date(int d, int m, int y) {
                day = d;
                month = m;
                year = y;
        }
        public Date (String s) {
                setDate(s);
        }
        public void setDate(String s){
                //two cases / format or - format
                //2019-1-23 or  1/23/2019
                if(s.contains("/")){
                        //"/" format use split on "/"
                        String[] st = s.split("/");
                        if(st.length != 3){
                                System.out.println("Too many ot too little slashes");
                        }else {
                                month = Integer.parseInt(st[0]);
                                day = Integer.parseInt(st[1]);
                                year = Integer.parseInt(st[2]);
                        }
                }else if(s.contains("-")){
                        // "-" format
                        String[] st = s.split("-");
                        if(st.length != 3){
                                System.out.println("Too many ot too little slashes");
                        }else {
                                year = Integer.parseInt(st[0]);
                                month = Integer.parseInt(st[1]);
                                day = Integer.parseInt(st[2]);
                                
                        }
                }else{
                        System.out.println("Invalid format");
                }
                
        }
        public int getDay() {
                return day;
        }
        public void setDay(int day) {
                this.day = day;
        }
        public int getMonth() {
                return month;
        }
        public void setMonth(int month) {
                this.month = month;
        }
        public int getYear() {
                return year;
        }
        public void setYear(int year) {
                this.year = year;
        }
        public String toString() {
                String st = month+"/" + day+ "/" + year;
                return st;
        }
        public boolean equals(Date d){
                return (this.day == d.day && this.month == d.month && this.year == d.year);
        }
        public boolean isBefore(Date d) {
                //returns true if d is before 
                if(d.year > this.year) 
                        return true;
                else if(year == d.year) {
                        if(d.month > this.month) 
                                return true;
                        else if(d.month == this.month) {
                                if(d.day > this.day )
                                        return true;
                        }
                }
                return false;//equal will be in the false
        }
        public int daysSince (Date d) {
                int days = 0;
                //your code to compute days goes here

            //daysSince(Date d) returns how many days from this date to date d 
                return days;
        }
}

Answer 1

If you have any doubts, please give me comment...

public class Date {

        static final int[] daysInMonth = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

        private int day, month, year;

        public Date() {

                day = 1;

                month = 1;

                year = 2000;

        }

        public Date(int d, int m, int y) {

                day = d;

                month = m;

                year = y;

        }

        public Date(String s) {

                setDate(s);

        }

        public void setDate(String s) {

                // two cases / format or - format

                // 2019-1-23 or 1/23/2019

                if (s.contains("/")) {

                        // "/" format use split on "/"

                        String[] st = s.split("/");

                        if (st.length != 3) {

                                System.out.println("Too many ot too little slashes");

                        } else {

                                month = Integer.parseInt(st[0]);

                                day = Integer.parseInt(st[1]);

                                year = Integer.parseInt(st[2]);

                        }

                } else if (s.contains("-")) {

                        // "-" format

                        String[] st = s.split("-");

                        if (st.length != 3) {

                                System.out.println("Too many ot too little slashes");

                        } else {

                                year = Integer.parseInt(st[0]);

                                month = Integer.parseInt(st[1]);

                                day = Integer.parseInt(st[2]);

                        }

                } else {

                        System.out.println("Invalid format");

                }

        }

        public int getDay() {

                return day;

        }

        public void setDay(int day) {

                this.day = day;

        }

        public int getMonth() {

                return month;

        }

        public void setMonth(int month) {

                this.month = month;

        }

        public int getYear() {

                return year;

        }

        public void setYear(int year) {

                this.year = year;

        }

        public String toString() {

                String st = month + "/" + day + "/" + year;

                return st;

        }

        public boolean equals(Date d) {

                return (this.day == d.day && this.month == d.month && this.year == d.year);

        }

        public boolean isBefore(Date d) {

                // returns true if d is before

                if (d.year > this.year)

                        return true;

                else if (year == d.year) {

                        if (d.month > this.month)

                                return true;

                        else if (d.month == this.month) {

                                if (d.day > this.day)

                                        return true;

                        }

                }

                return false;// equal will be in the false

        }

        public int daysSince(Date d) {

                int days = 0;

                // calculating days

                long n1 = year * 365 + day;

                for (int i = 1; i < month; i++)

                        n1 += daysInMonth[i];

                //calculating leap years;

                int yrs = year;

                if (month <= 2)

                        yrs--;

                n1 += yrs / 4 - yrs / 100 + yrs / 400;

                //calculating days

                long n2 = d.year * 365 + d.day;

                for (int i = 1; i < d.month; i++)

                        n2 += daysInMonth[i];

                //calculating leap years;

                yrs = d.year;

                if (d.month <= 2)

                        yrs--;

                n2 += yrs / 4 - yrs / 100 + yrs / 400;

                days = (int)(n2 - n1);

                return days;

        }

}