Thread: Checkerboard (asterisk pattern) problem

Hi guys, this is strictly NOT homework but my own home study. Using just While loops, I managed to create an asterisk checkerboard with 8 asterisk columns and rows usinhg my own code below:

public class Exe432 
{
    public static void main(String[] args) 
    {
        int line_number = 1;
        int asterisk_amount = 1;
 
        while ( line_number <= 8 )
        {
            while ( asterisk_amount <= 8 )
            {
                System.out.print( "* " );
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println();
            line_number += 1;
        }
    }
}

That's cool, but I need the checkerboard to have indented rows on some exactly as such below:

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *

Such a small problem but I'm finding it irritatingly difficult to make that one tweak. Added code to the one I already provided above is what I'd prefer thanks

Sorry guys, correction from last post. This is the checkerboard I need output from the code. Thanks.

* * * * * * * *
 * * * * * * * *
* * * * * * * *
 * * * * * * * *
* * * * * * * *
 * * * * * * * *
* * * * * * * *
 * * * * * * * *

Originally Posted by KevinWorkman

How did you make it happen when you typed it out? Do that in the code.

Hi Kevin. I'm not sure what you mean sorry.

Originally Posted by jjb1989

Hi guys, this is strictly NOT homework but my own home study. Using just While loops, I managed to create an asterisk checkerboard with 8 asterisk columns and rows usinhg my own code below:

public class Exe432 
{
    public static void main(String[] args) 
    {
        int line_number = 1;
        int asterisk_amount = 1;
 
        while ( line_number <= 8 )
        {
            while ( asterisk_amount <= 8 )
            {
                System.out.print( "* " );
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println();
            line_number += 1;
        }
    }
}

That's cool, but I need the checkerboard to have indented rows on some exactly as such below:

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *

Such a small problem but I'm finding it irritatingly difficult to make that one tweak. Added code to the one I already provided above is what I'd prefer thanks

insert the "\n" as following

 
public class Exe432 
{
    public static void main(String[] args) 
    {
        int line_number = 1;
        int asterisk_amount = 1;
 
        while ( line_number <= 8 )
        {
            while ( asterisk_amount <= 8 )
            {
                System.out.print( "* " );
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println("\n");
            line_number += 1;
        }
    }
}

Originally Posted by Voodoo

insert the "\n" as following

 
public class Exe432 
{
    public static void main(String[] args) 
    {
        int line_number = 1;
        int asterisk_amount = 1;
 
        while ( line_number <= 8 )
        {
            while ( asterisk_amount <= 8 )
            {
                System.out.print( "* " );
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println("\n");
            line_number += 1;
        }
    }
}

Thanks for your reply Voodoo. I'm afraid your tweak didn't produce the output I was looking for. Just to make myself more clearer, below is what I want my code to output:

* * * * * * * *
 * * * * * * * *
* * * * * * * *
 * * * * * * * *
* * * * * * * *
 * * * * * * * *
* * * * * * * *
 * * * * * * * *

Hey, what is your OS? On my PC (Windows Vista and Ubunto) it works! Have you this statement System.out.println("\n");?

sorry UBUNTU not ubunto

...by the way, try this:
[

by the way try this:

...
 
        while ( line_number <= 8 )
        {
            String tmp = "";
            while ( asterisk_amount <= 8 )
            {
                tmp += "* ";
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println(tmp+"\n");
            line_number += 1;
...

it's faster and less IO-overhead

oh...i misread your posting, terribly sorry. Here is the tweak:

 
        while ( line_number <= 8 )
        {
            String tmp = "";
            if ((line_number & 1) == 0) tmp = " ";
            while ( asterisk_amount <= 8 )
            {
                tmp += "* ";
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println(tmp+"\n");
            line_number += 1;
        }
..

Again, I need new glasses

Originally Posted by Voodoo

oh...i misread your posting, terribly sorry. Here is the tweak:

 
        while ( line_number <= 8 )
        {
            String tmp = "";
            if ((line_number & 1) == 0) tmp = " ";
            while ( asterisk_amount <= 8 )
            {
                tmp += "* ";
                asterisk_amount += 1;
            }
            asterisk_amount = 1;
            System.out.println(tmp+"\n");
            line_number += 1;
        }
..

Again, I need new glasses

Thanks again Voodoo lol. My OS is Windows 7. Your code did the trick thanks. If I can be just a slight more picky on the code, would you be kind enough to answer me the following:

I quote from my exercise book: Write an application that uses only the output statements

System.out.print( "* " );
System.out.print( " " );
System.out.println();

and While iteration only to produce checkerboard.

Sorry to be picky, but I'd like to keep to the exercise's demands so I don't drift off to any more advanced or more complex code than is required from the chapter. Thanks again!

Hi jjb1989
System.out.print() or System.out.println() is the invocation of the the method print() or println() of the Class PrintStream PrintStream (Java 2 Platform SE v1.4.2)
the print() method just prints as it is, the println() always terminates the line. If you use print() you have to care about the NewLine or so and, very important, to "flush" the "remaining" in the output buffer with flush(). Otherwise you may get an incomplete result (e.g. missing some characters in your printout) when your program terminates.
System.out.print( "* " ); write/print a string of an asterisk + a blank into the output buffer
System.out.print( " " ); write/print a string of "1 blank" into the output buffer
System.out.println(); insert a line-separator into output buffer and "flushes" the buffer out.
Okay?

Originally Posted by Voodoo

Hi jjb1989
System.out.print() or System.out.println() is the invocation of the the method print() or println() of the Class PrintStream PrintStream (Java 2 Platform SE v1.4.2)
the print() method just prints as it is, the println() always terminates the line. If you use print() you have to care about the NewLine or so and, very important, to "flush" the "remaining" in the output buffer with flush(). Otherwise you may get an incomplete result (e.g. missing some characters in your printout) when your program terminates.
System.out.print( "* " ); write/print a string of an asterisk + a blank into the output buffer
System.out.print( " " ); write/print a string of "1 blank" into the output buffer
System.out.println(); insert a line-separator into output buffer and "flushes" the buffer out.
Okay?

Thanks for the information Voodoo. I'm aware of what each of the methods do but have trouble using them and repetition to produce that checkerboard. I'm missing something and I just want to see the whole code as asked for by the exercise. Thanks again!

Originally Posted by jps

I will for now refrain from giving you the answer, but a nested for loop, and the % operator would be able to stagger the starting character, * or 'space', on staggered lines.


sorry, I missed that post..
If you think about what you intend to write one line at a time, one character at a time:

First line, first character, print("* "), second character print ("* ")
second line, first character, print(" "), second character print("* ")

Every other line you want to print a space before your series of "* ". Remember one loop is per line and one is per entry on the current line in the making.

Thanks jps, finally solved it! Thanks to Voodoo as well!