Attempting to print a calender put my output is displaying incorrectly

[abi]

This is what it should look like (a bit more aligned)
Feb 2012
Su Mo Tu We Th Fr Sa
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

what I am getting is:

Feb 2012
Su Mo Tu We Th Fr Sa
1
2 3 4 5 6 7 8
......
.....
...... 27

There seems to be a problem with the check for leap year and displaying the no. of days for feb because it should be 29 for 2012 as it is a leap year.
In general I think there is a problem with the no. of days displaying.

import java.util.Scanner;

public class Calender_b
{
  public static void main(String[] args)
  {
  Scanner input = new Scanner(System.in);

    //Prompt user for month and year

    System.out.print("Enter Month (1 - 12): ");
    int month = input.nextInt();
        while (month < 1 || month > 12 )
         {
          System.out.print("Enter Month (1 - 12): ");
           month = input.nextInt();
         }
        
    System.out.print("Enter Year (1900 - 2100): ");
    int year = input.nextInt();
        while (year < 1900 || year > 2100 )
         {
          System.out.print("Enter Year (1900 - 2100): ");
           year = input.nextInt();
         }   

   printMonth(month, year);
  } 

  public static void printMonth(int month, int year)
  {
  
    printMonthTitle(month, year);
    
    printMonthBody(month, year);

  }

  public static void printMonthTitle(int month, int year)
  {
    System.out.println("");
    System.out.println(" "+getMonthName(month) +"             "+ year);
    System.out.print("");
    System.out.println(" Su Mo Tu We Th Fr Sa ");
    

  }

  public static String getMonthName(int month)
  {

      String monthString = "";
    
      switch (month) 
      {
            case 1:  monthString = "Jan";
                     break;
            case 2:  monthString = "Feb";
                     break;
            case 3:  monthString = "Mar";
                     break;
            case 4:  monthString = "Apr";
                     break;
            case 5:  monthString = "May";
                     break;
            case 6:  monthString = "Jun";
                     break;
            case 7:  monthString = "Jul";
                     break;
            case 8:  monthString = "Aug";
                     break;
            case 9:  monthString = "Sep";
                     break;
            case 10: monthString = "Oct";
                     break;
            case 11: monthString = "Nov";
                     break;
            case 12: monthString = "Dec";
                     
     }
   
   return monthString;

  }
  
  public static void printMonthBody(int month, int year)
  {
     int startDay = getStartDay(month, year);
     int numberOfDays = getNumOfDaysInMonth(month, year);
    
     int i = 0;
     for (i = 0; i < startDay; i++)
       {
         System.out.print("  ");
       }

     for (i = 1; i < numberOfDays; i++)
       {
         System.out.printf("%3d", i);
       
         if((i + startDay) % 7 ==  0)
         {
          System.out.println();
         }
       }
    System.out.println("");
  }
   
  public static int getStartDay(int month, int year)
  {
     // declare variables needed for Rev.Zeller's algorithm
     int a = month, b = 1, c = year, d = year / 100 + 1;
      
     //compute the required quantities
       
       int w = ( 13 * a - 1 ) / 5;
       int x = c / 4;
       int y = d / 4;
       int z = w + x + y + b + c - 2 * d;
       int r = 0;
           if ( z > 0)
            {
             r = z % 7;
            }
           else
            {
             r = (r + 7) % 7;
            } 
  
     return r;
  }

  public static int getNumOfDaysInMonth(int month, int year)
  {
     int numDays = 0;

     //Find the no. of days in a month
   if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
    {
      numDays = 31;
    } 

   else if (month == 2)
    {
      
     if ( (year % 4 == 0) && (year % 400 == 0) && !(year % 100 == 0) )
      {
        numDays = 29;
      }
      else
      {
        numDays = 28;
      }
    }
   else
    {
     numDays = 30;
    } 
   return numDays;
  }


}

[Ronin]

Hi abi, there are two issues with your code.

Firstly, the 'if' statement on line 146 contains the following code:

(year % 400 == 0)

The year 2012 does not resolve to true for this condition causing your application to execute the 'else' statement.

Secondly, your 'for' loop on line 97 loops whilst 'i' is less than 'numberOfDays' causing your application to print out everything but the last day.
The easiest way to correct this is with the following:

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

Regards.

[abi]

I made the correction for the if on line 146 by putting and || instead of an &&.
And as for the for statement I made that correction soon after I posted this but it still shows Feb 2012 in that incorrect format with the days going up to 28.

Here is the link to the criteria of the assignment if you wanna look at it.
Programming Assignment 5

[Ronin]

Abi,

For the formatting have a look at number formatting. This can be done directly to the output...
Formatting Numeric Print Output (The Java™ Tutorials > Learning the Java Language > Numbers and Strings)

...or a string.
Strings (The Java™ Tutorials > Learning the Java Language > Numbers and Strings)

Your 'if' statement on line 146 needs some more work.
Have a look at the conditions for which Febuary has 29 days. Without looking at the latest code, you were mostly there with your initial attempt.

Regards.

[abi]

I've made changes to the code. And I am using the printf but I am still having trouble with the days output. The program complies but now I get some sort of a huge error message that says IllegalFOrmatConversion.

import java.util.Scanner;

public class Calendar_b
{
  public static void main(String[] args)
  {
  Scanner input = new Scanner(System.in);

    //Prompt user for month and year

    System.out.print("Enter Month (1 - 12): ");
    int month = input.nextInt();
        while (month < 1 || month > 12 )
         {
          System.out.print("Enter Month (1 - 12): ");
           month = input.nextInt();
         }
        
    System.out.print("Enter Year (1900 - 2100): ");
    int year = input.nextInt();
        while (year < 1900 || year > 2100 )
         {
          System.out.print("Enter Year (1900 - 2100): ");
           year = input.nextInt();
         }   
       

   printMonth(month, year);
  } 

  public static void printMonth(int month, int year)
  {
  
    printMonthTitle(month, year);
    
    printMonthBody(month, year);

  }

  public static void printMonthTitle(int month, int year)
  {

    System.out.println("");
    System.out.println(" "+getMonthName(month) +"             "+ year);
    System.out.print("");
    System.out.println(" Su Mo Tu We Th Fr Sa ");
    
  }

  public static String getMonthName(int month)
  {

      String monthString = "";
    
      switch (month) 
      {
            case 1:  monthString = "Jan";
                     break;
            case 2:  monthString = "Feb";
                     break;
            case 3:  monthString = "Mar";
                     break;
            case 4:  monthString = "Apr";
                     break;
            case 5:  monthString = "May";
                     break;
            case 6:  monthString = "Jun";
                     break;
            case 7:  monthString = "Jul";
                     break;
            case 8:  monthString = "Aug";
                     break;
            case 9:  monthString = "Sep";
                     break;
            case 10: monthString = "Oct";
                     break;
            case 11: monthString = "Nov";
                     break;
            case 12: monthString = "Dec";
                     
     }
   
   return monthString;

  }
  
  public static void printMonthBody(int month, int year)
  {
     int startDay = getStartDay(month, year);
     int numberOfDays = getNumOfDaysInMonth(month, year);
    
     int i = 0;
     for (i = 0; i < startDay; i++)
       {
         System.out.printf("%3s","");
       }

     for (i = 1; i <= numberOfDays; i++)
       {
         System.out.printf("%3d", i);
       
         if((i + startDay) % 7 ==  0)
         {
          System.out.println();
         }
       }
    System.out.println();
  }
  
  public static int changeMonth(int month)
  {
    int monthX = 0; 
  
    switch (month)
    {
            case 1:  monthX = 11;
                     break;
            case 2:  monthX = 12;
                     break;
            case 3:  monthX = 1;
                     break;
            case 4:  monthX = 2;
                     break;
            case 5:  monthX = 3;
                     break;
            case 6:  monthX = 4;
                     break;
            case 7:  monthX = 5;
                     break;
            case 8:  monthX = 6;
                     break;
            case 9:  monthX = 7;
                     break;
            case 10: monthX = 8;
                     break;
            case 11: monthX = 9;
                     break;
            case 12: monthX = 10;
    }                     
   return monthX;
  }

   
  public static int getStartDay(int month, int year)
  {
     int m = changeMonth(month);

   // declare variables needed for Rev.Zeller's algorithm
     int a = m, b = 1; 
     int c = 0;
      if (m == 11 || m == 12)
        {
          c = year - 1;
        }
       else 
        {
          c = year;
        }
     int d = 0;
     if(month <= 12 && year == 1900)
      {
        d = 19;  
      }
     else if ( year <= 2000 )
      {
        d = 20;
      }
     else
       {
         d = 21;
       }
      
     //compute the required quantities
       
       int w = ( 13 * a - 1 ) / 5;
       int x = c / 4;
       int y = d / 4;
       int z = w + x + y + b + c - 2 * d;
       int r = 0;
           if ( z > 0)
            {
             r = z % 7;
            }
           else
            {
             r = (r + 7) % 7;
            } 
       
  
     return r;
  }

  public static int getTotalNumberOfDays(int month, int year)
  {
    int total = 0;
   
    for(int i = 1900; i < year; i++)
     {
       if( (year % 4 == 0) || (year % 400 == 0) && !(year % 100 == 0) )
        {
          total += 366;
        }
       else
        {
          total += 365;
        }
     }
 
     for(int i = 1; i < month; i++)
      {
        total = total + getNumOfDaysInMonth(year, i);  
      }
     return total;
  }   

  public static int getNumOfDaysInMonth(int month, int year)
  {
     int numDays = 0;

     //Find the no. of days in a month
   if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
    {
      numDays = 31;
    } 

   else if (month == 2)
    {
      
     if ( (year % 4 == 0 && year % 100!= 0) || (year % 400 == 0)  )
      {
        numDays = 29;
      }
      else
      {
        numDays = 28;
      }
    }
   else
    {
     numDays = 30;
    } 
   return numDays;
  }


}

[abi]

This is the error
Feb 2012
Su Mo Tu We Th Fr Sa
Exception in thread "main" java.util.UnknownFormatConversionException: Conversio
n = '3'
at java.util.Formatter.checkText(Formatter.java:2547)
at java.util.Formatter.parse(Formatter.java:2533)
at java.util.Formatter.format(Formatter.java:2469)
at java.io.PrintStream.format(PrintStream.java:970)
at java.io.PrintStream.printf(PrintStream.java:871)
at Calendar_b.printMonthBody(Calendar_b.java:95)
at Calendar_b.printMonth(Calendar_b.java:36)
at Calendar_b.main(Calendar_b.java:28)

[Ronin]

Hi abi,

To format the output you need to use format() as opposed to printf(). Have another look at the first link I posted in #4, you can see an example about half way down.

Regards.

[Ronin]

Ignore #7, printf() and format() seem to do the same thing. I'll have another look at the code and get back to you.

Regards.

[Ronin]

The error is complaining about line 95 but this code runs ok on my machine with the ex.
What jdk / ide are you currently using?

Regards.

[abi]

Thanks for the help, and sorry for the late reply. I figured out what the problem was, it had to do with the parameters for printf().

Thanks