Thread: Help with formatting spacing on a calender grid please!

Hi all, beginning programmer here. What I am trying to do is get a small amount of input from the user (day of the week the year starts on, and the year itself), and output a text grid calender like this:

JAN of 2011
S M T W T F S
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31

There are three spaces between each date, and what I am trying to do is get the program to do is:
1) Begin a new line in the loop after the program reaches the seventh day <-- This has been achieved.
2) Print three spaces between each single digit <-- This has been achieved.
3) Print two spaces after each digit >= 10 .....which is where I'm stuck.

Here is my complete code:

import javax.swing.JOptionPane;
 
public class Calender {
 
public static void main(String[] args){
 
// Get year and start date from user
String yearString = JOptionPane.showInputDialog("Enter current year:");
int year = Integer.parseInt(yearString);
 
String startDateString = JOptionPane.showInputDialog(
	"Enter the day of the week for January 1:\n1 = Sunday \n2 = Monday \n3 = Tuesday" +
	"\n4 = Wednesday \n5 = Thursday \n6 = Friday \n7 = Saturday");
int startDate = Integer.parseInt(startDateString);
 
// Create loop for 12 months
for (int i = 1; i <= 12; i++){
	String month = "xxx";
	int days = 0;
	  switch (i){								// Switch statement for diff. months
	    case 1: month = "JAN";
	     days = 31;
	     break;
	    case 2:month = "FEB"; 	// FIX FOR LEAP YEAR EVENTUALLY!
	     days = 28;
	     break;
	    case 3:month = "MAR";
			 	     days = 31;
	     break;
	    case 4:month = "APR";
				     days = 30;
	     break;
	    case 5:month = "MAY";
				     days = 31;
	     break;
	    case 6:month = "JUN";
				     days = 30;
	     break;
	    case 7:month = "JUL";
				     days = 31;
	     break;
	    case 8:month = "AUG";
				     days = 31;
	     break;
	    case 9:month = "SEP";
				     days = 30;
	     break;
	    case 10:month = "OCT";
				     days = 31;
	     break;
	    case 11:month = "NOV";
				     days = 30;
	     break;
	    case 12:month = "DEC";
				     days = 31;
	     break;
   		}
 
  System.out.println("\n" + month + " of " + year);
	System.out.println("S   M   T   W   T   F   S");
 
		for (int j = 1; j < startDate; j++){		// Loop for formatting spacing for start date
    	             System.out.print("    ");
		}
 
			for (int j = 1, count = startDate; j <= days; j++, count++){			// Loop for outputting each day's number
				if (count % 7 == 0){
					System.out.println(j);
				}
/*
				if (count >= 10){
					System.out.print(j + "  ");
				}
*/
				else
					System.out.print(j + "   ");
 
			}
 
 
		}
 
	}
 
}

The output I get is perfect (minus the formatting for double-digit dates), but when I apply the commented code is when the troubles start:
if (count >= 10){
System.out.print(j + " ");
}

The output produced from this repeats Saturday's date on the next line, and properly applies the two spaces between numbers 10 and 15, but not between the erroneous duplicate 15 and 16, 22 and 23, and 29 and 30. I am extremely confused, so any and all help/advice would be greatly appreciated! Thanks guys!

Use the printf method instead. It allows you to specify the width of a column. That is if you want to print "hello" in a column with a width of 15 it will insert the 10 spaces for you. For "Master" it will insert 9 spaces.

Thanks that helps a bunch with the column formatting issue. But now it messed up my initial start date, and now every month inserts a space in the entire first row and starts every month on sunday no matter what the user inputs.

Here is the updated code that's still buggy

import javax.swing.JOptionPane;
 
public class Calender {
 
public static void main(String[] args){
 
// Get year and start date from user
String yearString = JOptionPane.showInputDialog("Enter current year:");
int year = Integer.parseInt(yearString);
 
String startDateString = JOptionPane.showInputDialog(
	"Enter the day of the week for January 1:\n1 = Sunday \n2 = Monday \n3 = Tuesday" +
	"\n4 = Wednesday \n5 = Thursday \n6 = Friday \n7 = Saturday");
int startDate = Integer.parseInt(startDateString);
 
// Create loop for 12 months
for (int i = 1; i <= 12; i++) {
	String month = "xxx";
	int days = 0;
	  switch (i){								// Switch statement for diff. months
	    case 1: month = "JAN";
	     days = 31;
	     break;
	    case 2:month = "FEB"; 	// FIX FOR LEAP YEAR EVENTUALLY!
	     days = 28;
	     break;
	    case 3:month = "MAR";
			 	     days = 31;
	     break;
	    case 4:month = "APR";
				     days = 30;
	     break;
	    case 5:month = "MAY";
				     days = 31;
	     break;
	    case 6:month = "JUN";
				     days = 30;
	     break;
	    case 7:month = "JUL";
				     days = 31;
	     break;
	    case 8:month = "AUG";
				     days = 31;
	     break;
	    case 9:month = "SEP";
				     days = 30;
	     break;
	    case 10:month = "OCT";
				     days = 31;
	     break;
	    case 11:month = "NOV";
				     days = 30;
	     break;
	    case 12:month = "DEC";
				     days = 31;
	     break;
   		}
 
  System.out.println("\n" + month + " of " + year);		// Header for each month
	System.out.println("S   M   T   W   T   F   S");
 
		for(int j = 1; j < startDate; j++){								// Loop for formatting spacing for start date
    	System.out.print("    ");
		}
 
			for(int k = 1, count = 0; k <= days; k++, count++){			// Loop for outputting each day's number
 
				count += startDate;
 
				if (count % 7 == 0){
					System.out.println();
				}
 
				System.out.printf("%-4d", k);
			}
 
 
		}
 
	}
 
}

1. You never change the value of startDate which means each month will be printed starting on the same day.
2. The order in which you print things matters.

Thanks man, I changed the order in which I printed the println statement and the formatting is now perfect. Your point #2 you made is spot on and I didn't notice it until just now... Thank you for that. I seem to be hitting a brick wall with regard to how to adjust the start date for each month based on the user only entering input for the starting day of the entire year once.

Here's a hint:

class Test {
    public static void main(String[] args) {
        int startDate = 6;
        int[] monthDays = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        String[] months = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",
                "Sep", "Oct", "Nov", "Dec"};
        String[] days = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
        for(int index = 0; index < months.length; index++) {
 
            System.out.println(months[index] + " begins on " + days[startDate]);
            startDate = (startDate + monthDays[index]) % 7;
        }
    }
}

Thanks so much. I really appreciate all the help you've given me tonight, very kind of you.

The thing is, I'm in an introductory Java class and we have not learned about arrays yet (that is what I assume the bracketed code is... from reading ahead a little in our textbood). Our instructor expected this program to be built without using arrays, I guess. Can this even be done without doing what you just did there?

I wasn't suggesting you use arrays. The formula as the last line in the loop is what is important as it shows how to calculate the startDate of the next month. Think about how you can replace accessing the monthDays array with something already in your code.

Originally Posted by bulx0001

Does the formula you gave me assume Saturday = day 6...

Yes it does since Saturday is in position 6 in the array. But I had to initialise startDate to be 6. Whereas you initialise it to be 7. Another problem is that using this formula when the start day is Saturday the value of startDate will be 0 as 35 % 7 == 0 and not 7. So either way you would have to do a bit of fiddling to get the exact startDate you want for each month.