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Ranch Hand
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It is said about flags in pritf in SCJP book,page 507



"+" Include a sign (+ or -) with this argument




I don't think this flag"+" could print negative numbers as book said.Which flag can print negative sign?


Another question:


about this line:



What do this mean: +-7?

When I try



It throws exception.
 
Bartender
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abalfazl hossein wrote:
"+" Include a sign (+ or -) with this argument


I don't think this flag"+" could print negative numbers as book said.Which flag can print negative sign?


Why not try it with a negative number and see what happens.




What do this mean: +-7?


The '+' does as detailed above, it appends a sign character to the number.
The '-7' means pad to 7 characters and left align, specifically '-' means left align but this is only meaningful if you specify a width to pad the number to (numbers are naturally right aligned), hence you get an exception if you use it without a width.
 
Marshal
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Don't use \n even if you found it in your book. Always use %n
You can find all the tags in the Formatter class. Beware: there are many many different tags.
 
Campbell Ritchie
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You always get some sort of sign of a number being negative. What the + option means is it prints a sign when the number is positive, too.
 
Bartender
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Campbell Ritchie wrote:You always get some sort of sign of a number being negative. What the + option means is it prints a sign when the number is positive, too.


Or zero.
 
Campbell Ritchie
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Forgot about zero. Thank you.
 
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In the real world coding i never come across these kind of scenarios SCJP asks
 
It is sorta covered in the JavaRanch Style Guide.
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