The document outlines the requirements for a Java program that calculates the number of days between two user-input dates without using advanced date imports. It includes examples of inputs and expected outputs, as well as a substantial code snippet that demonstrates input validation and day calculations, although it highlights difficulties in getting correct results. The code structure involves looping for input until valid dates are entered and then performing calculations based on the months and days.

1. Need to make a Java program which calculates the number of days between two dates. I am NOT
able to use anything too advanced yet such as import.java.util.Calender, import.java.util.Date; or
import.java.util.GregorianCalender; Here are a couple of examples of what is should look like
when complete. I am having troubles getting my calculations to come out correctly. I’ve also
written the code I have so far.
EXAMPLE
“Enter first date now:
Enter Month: 1
Enter Day: 1
Enter Year: 1900
Enter the second date:
Enter Month: 1
Enter Day: 1
Enter Year: 2400
The first date is: 1/1/1900
The other date is: 1/1/2400
The total number of days between the dates is 182621”
AND
“Enter first date now:
Enter Month: 2
Enter Day: 23
Enter Year: 2016
Enter the second date:
Enter Month: 11
Enter Day: 30
Enter Year: 1955
The first date is: 2/23/2016
The other date is: 11/30/1955
The total number of days between the dates is 22000”
Here is what I have so far:
Import java.util.Scanner;
Public class dates {
Public static void main ( String args [] ) {
int monthOne;
int monthTwo;

2. int dayOne;
int dayTwo;
intyearOne;
intyearTwo;
Scanner get = new Scanner (System.in );
System.out.println ( “Enter first date now: “ );
do {
System.out.print ( “Enter Month: “);
monthOne = get.nextInt();
System.out.print ( “Enter Day: “ );
dayOne = get.nextInt();
System.out.print ( “Enter Year : “ );
yearOne = get.nextInt();
if (monthOne < 1 || monthOne > 12 ) {
System.out.printf ( “%d is not a valid month ”, monthOne ); }
If ( (!(yearOne % 4 == 0 && yearOne & 100 !=0 || yearOne % 400 == 0) && (monthOne == 2
&& dayOne >= 29)) || ((yearOne % 4 == 0 && yearOne % 100 != 0 || yearOne % 400 == 0) &&
(monthOne == 2 && dayOne >= 30))) {
System.out.printf ( “%d is not a valid day. ”, dayOne ); }
If ( (monthOne == 4 && dayOne > 30) || (monthOne ==6 && dayOne > 30) || (monthOne == 9
&& dayOne > 30) || (monthOne == 11 && dayOne > 30) || (dayOne < 1 || dayOne > 31)) {
System.out.printf ( “%d is not a valid day. ”, dayOne );
If ( yearOne < 1900 || yearOne > 2400 ) {
System.out.printf ( “%d is not a valid year. ”, yearOne ); }
} while (( (!(yearOne % 4 == 0 && yearOne % 100 !=0 || yearOne % 400 == 0) && (monthOne
== 2 && dayOne >= 29)) || ((yearOne % 4 == 0 && yearOne % 100 != 0 || yearOne % 400 ==
0) && (monthOne == 2 && dayOne >= 30 )) || (monthOne == 4 && dayOne > 30) || (monthOne
== 6 && dayOne > 30) || (monthOne == 9 && dayOne > 30) || (monthOne == 11 && dayOne >
30) || (monthOne < 1 || monthOne > 12) || (dayOne < 1 || dayOne > 31) || (yearOne < 1900 ||
yearOne > 2400) ));
System.out.printf ( “ Enter the second date: ” );
do {
System.out.print ( “Enter Month: “);
monthTwo = get.nextInt();
System.out.print ( “Enter Day: “ );
dayTwo = get.nextInt();

3. System.out.print ( “Enter Year : “ );
yearTwo = get.nextInt();
if (monthTwo < 1 || monthTwo > 12 ) {
System.out.printf ( “%d is not a valid month ”, monthTwo ); }
If ( (!(yearTwo % 4 == 0 && yearTwo & 100 !=0 || yearTwo % 400 == 0) && (monthTwo == 2
&& dayTwo >= 29)) || ((yearTwo % 4 == 0 && yearTwo % 100 != 0 || yearTwo % 400 == 0)
&& (monthTwo == 2 && dayTwo >= 30))) {
System.out.printf ( “%d is not a valid day. ”, dayTwo ); }
If ( (monthTwo == 4 && dayTwo > 30) || (monthTwo ==6 && dayTwo > 30) || (monthTwo ==
9 && dayTwo > 30) || (monthTwo == 11 && dayTwo > 30) || (dayTwo < 1 || dayTwo > 31)) {
System.out.printf ( “%d is not a valid day. ”, dayTwo );
If ( yearTwo < 1900 || yearTwo > 2400 ) {
System.out.printf ( “%d is not a valid year. ”, yearTwo ); }
} while (( (!(yearTwo % 4 == 0 && yearTwo % 100 !=0 || yearTwo % 400 == 0) &&
(monthTwo == 2 && dayTwo >= 29)) || ((yearTwo % 4 == 0 && yearTwo % 100 != 0 ||
yearTwo % 400 == 0) && (monthTwo == 2 && dayTwo >= 30 )) || (monthTwo == 4 &&
dayTwo > 30) || (monthTwo == 6 && dayTwo > 30) || (monthTwo == 9 && dayTwo > 30) ||
(monthTwo == 11 && dayTwo > 30) || (monthTwo < 1 || monthTwo > 12) || (dayTwo < 1 ||
dayTwo > 31) || (yearTwo < 1900 || yearTwo > 2400) ));
System.out.printf ( “ The first date is: %d/%d/%d ”, monthOne, dayOne, yearOne );
System.out.printf ( “ The other date is: %d/%d/%d ”, monthTwo, dayTwo, yearTwo );
int totalDayOne = 0;
int numDaysJan = dayOne;
int numDaysFeb = 31 + dayOne;
int numDaysMar = 31 + 28 + dayOne;
int numDaysApr = 31 + 28 + 31 + dayOne;
int numDaysMay = 31 + 28 + 31 + 30 + dayOne;
int numDaysJun = 31 + 28 + 31 + 30 + 31 + dayOne;
int numDaysJul = 31 + 28 + 31 + 30 + 31 + 30 + dayOne;
int numDaysAug = 31 + 28 + 31 + 30 + 31 + 30 + 31 + dayOne;
int numDaysSep = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + dayOne;
int numDaysOct = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + dayOne;
int numDaysNov = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + dayOne;
int numDaysDec = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + dayOne;
int totalDayTwo = 0;
int numDaysJanTwo = dayTwo;

4. int numDaysFebTwo = 31 + dayTwo;
int numDaysMarTwo = 31 + 28 + dayTwo;
int numDaysAprTwo = 31 + 28 + 31 + dayTwo;
int numDaysMayTwo = 31 + 28 + 31 + 30 + dayTwo;
int numDaysJunTwo = 31 + 28 + 31 + 30 + 31 + dayTwo;
int numDaysJulTwo = 31 + 28 + 31 + 30 + 31 + 30 + dayTwo;
int numDaysAugTwo = 31 + 28 + 31 + 30 + 31 + 30 + 31 + dayTwo;
int numDaysSepTwo = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + dayTwo;
int numDaysOctTwo = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + dayTwo;
int numDaysNovTwo = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + dayTwo;
int numDaysDecTwo = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + dayTwo;
if ( monthOne == 1 ) {
totalDayOne += numDaysJan;
}
if ( monthOne == 2 ) {
totalDayOne += numDaysFeb;
}
if ( monthOne == 3 ) {
totalDayOne += numDaysMar;
}
if ( monthOne == 4 ) {
totalDayOne += numDaysApr;
}
If ( monthOne == 5 ) {
totalDayOne += numDaysMay;
}
if (monthOne == 6 ) {
totalDayOne += numDaysJun;
}
if ( monthOne == 7 ) {
totalDayOne += numDaysJul;
}
if ( monthOne == 8 ) {
totalDayOne += numDaysAug;
}
if ( monthOne == 9 ) {

5. totalDayOne += numDaysSep;
}
if ( monthOne == 10 ) {
totalDayOne += numDaysOct;
}
if (monthOne == 11 ) {
totalDayOne += numDaysNov;
}
if (monthOne == 12 ) {
totalDayOne += numDaysDec;
}
if ( monthTwo == 1 ) {
totalDayTwo += numDaysJanTwo;
}
if ( monthTwo == 2 ) {
totalDayTwo += numDaysFebTwo;
}
if ( monthTwo == 3 ) {
totalDayTwo += numDaysMarTwo;
}
if ( monthTwo == 4 ) {
totalDayTwo += numDaysAprTwo;
}
If ( monthTwo == 5 ) {
totalDayTwo += numDaysMayTwo;
}
if (monthTwo == 6 ) {
totalDayTwo += numDaysJunTwo;
}
if ( monthTwo == 7 ) {
totalDayTwo += numDaysJulTwo;
}
if ( monthTwo == 8 ) {
totalDayTwo += numDaysAugTwo;
}
if ( monthTwo == 9 ) {

6. totalDayTwo += numDaysSepTwo;
}
if ( monthTwo == 10 ) {
totalDayTwo += numDaysOctTwo;
}
if (monthTwo == 11 ) {
totalDayTwo += numDaysNovTwo;
}
if (monthTwo == 12 ) {
totalDayTwo += numDaysDecTwo;
}
int daysBetween = totalDayOne – totalDayTwo;
if ( totalDayOne < totalDayTwo ) {
daysBetween = totalDayTwo – totalDayOne;
}
int daysTotal = 0;
while ( yearOne < yearTwo ) {
yearOne++;
if ( yearOne % 4 == 0 && yearOne % 100 != 0 || yearOne % 400 == 0)
daysTotal += 366;
else
daysTotal += 365;
}
while ( yearTwo < yearOne ) {
yearTwo++;
if ( yearTwo % 4 == 0 && yearTwo % 100 != 0 || yearTwo % 400 == 0)
daysTotal += 366;
else
daysTotal += 365;
}
System.out.printf ( “ The total number of days between the dates is %d ”, daysTotal +
daysBetween);
}
}
Solution

7. import java.util.Calendar;
import java.util.Date;
import java.util.Scanner;
public class NewDateDifference {
public static void main(String[] args) {
System.out.print("Insert first date : ");
Scanner s = new Scanner(System.in);
String[] eingabe1 = new String[3];
while (s.hasNext()) {
int i = 0;
insert1[i] = s.next();
if (!s.hasNext()) {
s.close();
break;
}
i++;
}
System.out.print("Insert second date : ");
Scanner t = new Scanner(System.in);
String[] insert2 = new String[3];
while (t.hasNext()) {
int i = 0;
insert2[i] = t.next();
if (!t.hasNext()) {
t.close();
break;
}
i++;
}
Calendar cal = Calendar.getInstance();
cal.set(Calendar.DAY_OF_MONTH, Integer.parseInt(insert1[0]));
cal.set(Calendar.MONTH, Integer.parseInt(insert1[1]));
cal.set(Calendar.YEAR, Integer.parseInt(insert1[2]));
Date firstDate = cal.getTime();
cal.set(Calendar.DAY_OF_MONTH, Integer.parseInt(insert2[0]));

8. cal.set(Calendar.MONTH, Integer.parseInt(insert2[1]));
cal.set(Calendar.YEAR, Integer.parseInt(insert2[2]));
Date secondDate = cal.getTime();
long diff = secondDate.getTime() - firstDate.getTime();
System.out.println ("Days: " + diff / 1000 / 60 / 60 / 24);
}
}