can't explain!

[Jonathan]

// [e-mail]

// Prince, Jonathan
// Prompts for and reads a date as well as outputs the number of days from
// the beginning of the year and and the date of the next day

import java.util.Scanner;

public class LeapYears
{
public static void main(String[] args)
{

/****************************/
int month;
int day;
int year;


final int JAN = 31;
final int FEBLEAP = 28;
final int FEBNONLEAP = 29;
int FEB;
final int MAR = 31;
final int APRIL = 30;
final int MAY = 31;
final int JUNE = 30;
final int JULY = 31;
final int AUG = 31;
final int SEPT = 30;
final int OCT = 31;
final int NOV = 30;
final int DEC = 31;
final int THIRTYDAYS = 30;
final int THIRTYONEDAYS = 31;



boolean isLeapYear;
/****************************/


/****Get input****/
Scanner keyboard = new Scanner(System.in);

System.out.print("Enter a date: (year month day): ");
year = keyboard.nextInt();
month = keyboard.nextInt();
day = keyboard.nextInt();
/*****************/


/****Validate year****/
if (year < 1583)
{
System.out.println("ERROR: The year entered is invalid.");
System.exit(0); // Terminate program
System.out.println("The year is: " + year);
}
/*********************/


/****Is it a leap year?****/
isLeapYear = (year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0);


/****Determine days in Feb.****/
if (isLeapYear)
{
FEB = 29;
}

else
{
FEB = 28;
}
/******************************/


/****Validate month****/
if( (month < 1) || (month > 12) )
{
System.out.println("ERROR: The month entered is invalid.");
System.exit(0); // Terminate program
}
/**********************/


/****Validate day****/
boolean isValidDay = true; // initial assumption
switch(month)
{
case 2:
isValidDay = (day >=1) && (day <= FEB) ;
break;
case 4: case 6: case 9: case 11:
isValidDay = (day >=1) && (day <= THIRTYDAYS) ;
break;
default:
isValidDay = (day >=1) && (day <= THIRTYONEDAYS) ;
break;
}

if( ! isValidDay )
{
System.out.println("ERROR: The day entered is invalid.");
System.exit(0); // Terminate program
}
/********************/


/****Get Month's name****/
String monthName = "Unknown";
int monthDays = 0;
switch (month)
{
case 1: monthName = "January";
monthDays = JAN;
if(day>=JAN) monthName = "February";
break;

case 2: monthName = "February";
monthDays = FEB;
if(day>=FEB) monthName = "March";
break;

case 3: monthName = "March";
monthDays = MAR;
if(day>=MAR) monthName = "April";
break;

case 4: monthName = "April";
monthDays = APRIL;
if(day>=APRIL) monthName = "May";
break;

case 5: monthName = "May";
monthDays = MAY;
if(day>=MAY) monthName = "June";
break;

case 6: monthName = "June";
monthDays = JUNE;
if(day>=JUNE) monthName = "July";
break;

case 7: monthName = "July";
monthDays = JULY;
if(day>=JULY) monthName = "August";
break;

case 8: monthName = "August";
monthDays = AUG;
if(day>=AUG) monthName = "September";
break;

case 9: monthName = "September";
monthDays = SEPT;
if(day>=SEPT) monthName = "October";
break;

case 10: monthName = "October";
monthDays = OCT;
if(day>=OCT) monthName = "November";
break;

case 11: monthName = "November";
monthDays = NOV;
if(day>=NOV) monthName = "December";
break;

case 12: monthName = "December";
monthDays = DEC;
if(day>=DEC) monthName = "January";
break;
} /****Closes switch****/

/****Outputs the Date****/
System.out.println("The date is: " + monthName + " " + day + ", " + year + ".");


/****Discerning the day's position of the year.****/
int totalDays = 0;

if(month == 1)
totalDays = day;

else if(month == 2)
totalDays = JAN + day;

else if(month == 3)
totalDays = JAN + FEB + day;

else if(month == 4)
totalDays = JAN + FEB + MAR + day;

else if(month == 5)
totalDays = JAN + FEB + MAR + APRIL + day;

else if(month == 6)
totalDays = JAN + FEB + MAR + APRIL + MAY + day;

else if(month == 7)
totalDays = JAN + FEB + MAR + APRIL + MAY + JUNE + day;

else if(month == 8)
totalDays = JAN + FEB + MAR + APRIL + MAY + JUNE + JULY + day;

else if(month == 9)
totalDays = JAN + FEB + MAR + APRIL + MAY + JUNE + JULY + AUG + day;

else if(month == 10)
totalDays = JAN + FEB + MAR + APRIL + MAY + JUNE + JULY + AUG + SEPT + day;

else if(month == 11)
totalDays = JAN + FEB + MAR + APRIL + MAY + JUNE + JULY + AUG + SEPT + OCT + day;

else if(month == 12)
totalDays = JAN + FEB + MAR + APRIL + MAY + JUNE + JULY + AUG + SEPT + OCT + NOV + day;
/**************************************************/


/****Outputs the number of days that have passed so far****/
System.out.println(totalDays + " days have passed so far this year. ");


/****Find the next Day****/
int nextDay = 0;
nextDay = day + 1;

switch(month)
{
case 2:
if(day >= FEB)
nextDay = 1;
month++;
if( month > 12)
{
month = 1;
year++;
}

case 4: case 6: case 9: case 11:
if(day == 30)
nextDay = 1;
month++;

if( month > 12)
{
month = 1;
year++;
}

default:
if(day == 31)
nextDay = 1;
month++;
if( month > 12)
{
month = 1;
year++;
}
}/****close switch****/









/****Outputs the next day's date.****/
System.out.println("The next day is: " + monthName + " " + nextDay + ", " + year + ".");

} // main
} // class LeapYears

[Nauren]

is this a clock? lol

[Markus]

I remember doing that. We used C+ though iirc... It was a shitty class, because everyone in it had PCs and were fucking computer jocks... The teacher didnt actually teach anything... I passed programming I and I was completely fucked in programming II ><

Good luck! I want to go back

[lolAerya]

rather long program for such a simple task
what if I put the month is 13? error error
u have a switch and a if checking the same thing too

[mirowr]

AP Java was a whore of a class

[Axia]

This is how I would have handled it.

class jyear { //an object modelling a year, it contains 12 month objects in an array.

private jmonth jmonthArray[]; //said array

public jyear(int year) { //constructor. Initializes month array
for(int i=0; i<13; i++) {
this.jmonthArray = new jmonth(year, i);
}
}

public boolean isLeap() { //returns true if year is a leapyear, it does this by checking the length of February, which is in array position 1. All months are offset by 1 in the array, since the array starts at 0
if(jmonthArray[1].getLength == 29) return true;
else return false;
}

public int getDay(int month, int day) { //returns the number of the day given a date, uses a for statement to iterate down the array and sum lenghts up to the month prior to the month in question.
int count = 0;
for (int i = 0; int i < month-1; i++) {
count += jmonthArray.getLength();
}
return count+day;
}

public String getDayOrdinal(int month, int day) {
Same as getDay() but returns as a String with ordinal
int dayAtHand = this.getDay(month, day);
int ordinalTest = dayAtHand % 10;
if(ordinalTest == 1) return dayAtHand + "st";
if(ordinalTest == 2) return dayAtHand + "nd";
if(ordinalTest == 3) return dayAtHand + "rd";
return dayAtHand + "th";
}
}

class jmonth {

private static final String monthNamesArray[] = {"January", "February", "March", ...}; //all month names
private String name;
private int length;

public jmonth(int year, int month) {//initilizes the name of month and length
switch(month) {
case 2:
if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) this.length = 29; else this.length = 28;
break;
case: 4: case: 6 case 9: case 11:
this.length = 30;
break;
default:
this.length = 31;
}
this.name = monthNamesArray[month-1];
}

//accessor functions
public int getLength() {return this.length;}
public String getName() {return this.name;}
}

//Main function here. I hijacked your data collection code. All the main function does is build a year, and outputs two statements telling the person running the program what day it is in that year.
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);

System.out.print("Enter a date: (year month day): ");
int year = keyboard.nextInt();
int month = keyboard.nextInt();
int day = keyboard.nextInt();

jyear yearAtHand = new jyear(year);
System.out.println("The date given, " + month + "/" + day + "/" + year + ", is the " + yearAtHand.getDayOrdinal(month, day) + " day of the year.");
System.out.println("The next day is the " + yearAtHand.getDayOrdinal(month, day+1) + "day of the year.";
}

A lot of this is fluff. Given the purpose of the program, I don't see you really needing to name each month, but I kept that feature in there since you seemed to think it important enough to code. I also provided a function that returns the day as a string with its ordinal (1st as opposed to 1, 2nd as opposed to 2, etc.), strictly for aesthetic and reporting purposes. I never ran nor compiled this code, but it should be mostly proper. The only things I don't recall off the top of my head is how to initialize an array in one line (it would be better to enumerate a set of constants, but meh), and I'm sure there a few bugs in there (because there always are). But that's how I would have handled this program.

Mod: Oh, likewise, I ignored any error checking because I'm lazy.

-Axia

[Axia]

Looking at Jon's initial post again, I'm not even sure he was asking for help. >.> (Though why else he'd post this here, I have no idea).

[estara]

@.@ none of it makes any sense @.@

[Kaifu1]

+1

Wow Codeine, that sure is catchy.

I need to learn more about computers... and if this is it, I'm afraid of what I don't know.

[lolAerya]

(Huh?!) codeine? (Where?)

[Kaifu1]

the +1 thing. He's trying to "catch phrase" it.

[lolAerya]

oh lol ya, for sure ^^

[scolas]

You dont really need to know how to program to know about computers =) this is just for the geekier group ;-)

I remember all my programming classes... and programming contests .... what a geek i am

Geekness = Geekness + 1

fo sho

[Kaifu1]

I have a D20 and all the D&D books you could shake a Dwarf at.

[scolas]

I have 13.8 gb of D&D books on my laptop i take with me to D&D every sunday.... lol and i have about 300$ in dice =/