• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Ron McLeod
  • Rob Spoor
  • Tim Cooke
  • Junilu Lacar
Sheriffs:
  • Henry Wong
  • Liutauras Vilda
  • Jeanne Boyarsky
Saloon Keepers:
  • Jesse Silverman
  • Tim Holloway
  • Stephan van Hulst
  • Tim Moores
  • Carey Brown
Bartenders:
  • Al Hobbs
  • Mikalai Zaikin
  • Piet Souris

Dan's - Math.abs Question..

 
Greenhorn
Posts: 10
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Dan,
For the below program why 'f' is also included in the answer.
Which of the following statements are true in terms of the java.lang.Math.abs method?
a. Four overloaded versions of abs exist.
b. An ArithmeticException is declared in the throws clause.
c. The type of the return value depends on the type of the argument.
d. The returned value is always of a floating-point primitive type.
e. If the argument is greater than or equal to zero then the returned value is equal to the argument.
f. If the argument, arg, is less than zero then the returned value is -arg.
Thx
 
Ranch Hand
Posts: 1090
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Samy
This is because -arg for a -ve no. will be-(-ve no.). So this will make it positive.
 
Ranch Hand
Posts: 270
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
quote from api

public static int abs(int a)Returns the absolute value of an int value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned.
Note that if the argument is equal to the value of Integer.MIN_VALUE, the most negative representable int value, the result is that same value, which is negative.


As you can see here for negative values, their negation will be returned. And specially for Integer.MIN_VALUE, its negation is just the same as itself and so is Long.MIN_VALUE.
It could be wrong also if the statement is changed to:

The value returned is always non-negative.

 
Greenhorn
Posts: 4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
So the option 'f' shouldn't be true 'cause for the Integer.MIN_VALUE and Long.MIN_VALUE, the pass-in parameter and return value are the same, both negative. Right?
 
Ranch Hand
Posts: 1865
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Originally posted by Jim Kirkby:
So the option 'f' shouldn't be true 'cause for the Integer.MIN_VALUE and Long.MIN_VALUE, the pass-in parameter and return value are the same, both negative. Right?


The source code for the Math.abs method is as follows.

In my opinion, it is always correct to say the following.

If the argument, arg, is less than zero then the returned value is -arg.


In my opinion, the fact that the negation of negative infinity is the same as negative infinity doesn't violate the above quote.
 
Ranch Hand
Posts: 1561
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I had the same confusion
here...
 
reply
    Bookmark Topic Watch Topic
  • New Topic