formatting

[Ankur kothari]

■ "-" Left justify this argument
■ "+" Include a sign (+ or -) with this argument
■ "0" Pad this argument with zeroes
■ "," Use locale-specific grouping separators (i.e., the comma in 123,456)
■ "(" Enclose negative numbers in parentheses



can anyone explain all these things....specially the padding thing or give me a link

thank you

[Ankit Garg]

It is explained quite well on page 508 of the K&B book. Its also explained on the Formatter class docs. Try to create some programs to experiment with the things...

[Ankur kothari]

yes sir....

 
public class TestFormat
{
public static void main(String args[])
	{
	Boolean b=new Boolean(null);
	Boolean b1=new Boolean(true);
	Boolean b2=new Boolean(false);
	Boolean b3=new Boolean("true");
	Boolean b4=new Boolean("ankur");
	String s="ankur";
	System.out.format("%b %b %b %B %b %s\n",b,b1,b2,b3,b4,s);
	System.out.printf("%+06d %(,06d %,6d",5,-50000,54000);
	System.out.printf(" %-6d %4d",567,1234);

	}
}   

means ( removes the - sign and wraps around the number

rest are all clear....nothing better than trying it

[Ankur kothari]

  public class TestFormat
{
public static void main(String args[])
	{
	Boolean b=new Boolean(null);
	Boolean b1=new Boolean(true);
	Boolean b2=new Boolean(false);
	Boolean b3=new Boolean("ankur");
	System.out.printf("%b %b %b %b",b,b1,b2,b3);
	}
}  

why is b3 false....
If the argument arg is null, then the result is "false". If arg is a boolean or Boolean, then the result is the string returned by String.valueOf(). Otherwise, the result is "true".

according to this shouldnt it be true?

[rohan yadav]

Hi Ankur, I think anything other than true is considered false by Boolean(String) constructor.
So when toString() method gets called for Boolean constructor it returns the "ankur' (in your case). So apart from true anything passed as string to considered as a false

[Ankur kothari]

Otherwise, the result is "true".

what does this mean then?

[rohan yadav]

It means anything you pass to Boolean constructor. Suppose
check out following program

 class Test1
{
public static void main(String args[])
{
	System.out.println(new Boolean("rohan"));
	System.out.println(new Boolean("true"));
	System.out.println(new Boolean("false"));
	System.out.println(new Boolean("TRUE"));
}
}     

The output is
false
true
false
true

Did you clear what i mean??

[Ankur kothari]

understood what you are saying...but "otherwise its true" this really confuses me

[rohan yadav]

Sorry in hurry i typed something weired. Are you preparing for SCJP??

[Ankur kothari]

Thanks Rohan.....i got what you said...but its the language of the doc that confused me

[Ankur kothari]

yup i am preparing