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String formatting question

 
Greenhorn
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Hi,
I found this in the JQPlus mock exam:

could you please explain to me why this piece of code:


changes the -2222 to -2,222? (or o be precise it prints out "-2,222")?

K & B book says the comma causes the usage of locale-specific grouping operators, but why is the comma added after the first 2?

Thanks,
Justyna
 
Ranch Hand
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I'm not sure what your locale is, but I know in the US it's common to write a comma to seperate groups of three digits.
 
Ranch Hand
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My question is why do you have to use escape character when you can use like this,

System.out.printf("%,d",ii);



I believe by default it uses US locale unless you want to define locale using following method,

printf(Locale l,
String format,
Object... args)

 
Sheriff
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Originally posted by Venkat Sidh:
My question is why do you have to use escape character...


In this example, double quotes are supposed to be part of the output, so the escape sequence is needed. These are not part of the format specifier, which is simply %,d . If you did not want the output to appear within double quotes, you would not need the escape sequences.
 
Venkat Sidh
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Sorry, I missed out that it is part of output.....I still need to improve to find these gotchas.
 
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