Thread: Calendar Program Help

So i am new to java programming. My University Professor assigned us a Lab to have a user input a year and a month so it displays the correct amount of days in a month etc. He told us to just find the "logic" error in the program and fix it. He also said "NOT" to make a new method or anything at all, just fix something within the program he gave us. I know the error appears when i put in Feb. 2012. This month should have 29 days. The first of the month being a Wednesday, and the last day of the month should be the 29th and also a Wednesday. I have a feeling you have to code in the formula for leap year which is (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) but i do not know where to type this in the given code. Or maybe i don't even need that formula? Again im new to programming. And again he told us NOT to make a new method, just fix the logic error....Any help is appreciated, here is the given code i have to work with.......Thanks

import java.util.Scanner;

public class Lab1 {
/** Main method */
public static void main(String[] args) {
// Prompt the user to enter year
Scanner input = new Scanner(System.in);

// Prompt the user to enter year
System.out.print("Enter full year (e.g., 2001): ");
int year = input.nextInt();

// Prompt the user to enter month
System.out.print("Enter month in number between 1 and 12: ");
int month = input.nextInt();

// Print calendar for the month of the year
printMonth(year, month);
}

/** Print the calendar for a month in a year */
static void printMonth(int year, int month) {
// Print the headings of the calendar
printMonthTitle(year, month);

// Print the body of the calendar
printMonthBody(year, month);
}

/** Print the month title, e.g., May, 1999 */
static void printMonthTitle(int year, int month) {
System.out.println(" " + getMonthName(month)
+ " " + year);
System.out.println("-----------------------------");
System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
}

/** Get the English name for the month */
static String getMonthName(int month) {
String monthName = null;
switch (month) {
case 1: monthName = "January"; break;
case 2: monthName = "February"; break;
case 3: monthName = "March"; break;
case 4: monthName = "April"; break;
case 5: monthName = "May"; break;
case 6: monthName = "June"; break;
case 7: monthName = "July"; break;
case 8: monthName = "August"; break;
case 9: monthName = "September"; break;
case 10: monthName = "October"; break;
case 11: monthName = "November"; break;
case 12: monthName = "December";
}

return monthName;
}

/** Print month body */
static void printMonthBody(int year, int month) {
// Get start day of the week for the first date in the month
int startDay = getStartDay(year, month);

// Get number of days in the month
int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);

// Pad space before the first day of the month
int i = 0;
for (i = 0; i < startDay; i++)
System.out.print(" ");

for (i = 1; i <= numberOfDaysInMonth; i++) {
if (i < 10)
System.out.print(" " + i);
else
System.out.print(" " + i);

if ((i + startDay) % 7 == 0)
System.out.println();
}

System.out.println();
}

/** Get the start day of month/1/year */
static int getStartDay(int year, int month) {
return getDayofWeek(year, month, 1);
}

public static int getDayofWeek(int year, int month, int dayOfMonth) {
if (month == 1) {
month = 13;
year--;
}
else if (month == 2) {
month = 14;
year--;
}

int k = year % 100;
int j = (int)(year / 100);

int dayOfWeek = (int)(dayOfMonth + (int)((month + 1) * 26.0 / 10)
+ k + (int)(k / 4.0) + (int)(j / 4.0) + 5 * j) % 7;

return (dayOfWeek + 6) % 7;
}

/** Get the number of days in a month */
static int getNumberOfDaysInMonth(int year, int month) {
if (month == 1 || month == 3 || month == 5 || month == 7 ||
month == 8 || month == 10 || month == 12)
return 31;

if (month == 4 || month == 6 || month == 9 || month == 11)
return 30;

if (month == 2) return 28;

return 0; // If month is incorrect
}

}

omg! it worked!! Thank You! But I can't believe how i couldn't figure out how to write and where to write this 1 line of a simple code......

Good post Whitesoup12. I wonder why the Prof. wanted to return 0 as an error. I was taught to return -1 instead.

yea thanks for the posts WhiteSoup12 it's helping us new programmers understand more. what editing software are you using to write your code? i connect to my schools software from home. i downloaded eclipse but it didn't work for me for some reason