Math class

[Chitra AP]

Hi All,

K&B book says ceil(), floor() and round() all return integer equivalent floating-point numbers. But the following code prints

System.out.println(Math.round(1.1)); //prints 1
System.out.println(Math.ceil(1.1)); // prints 2.0

The first line should print 1.0, correct? Thanks.

[Whitney M. Davis]

Hi,

The two signatures of round() are:
public static int round(float)
public static long round(float)

This is something very important to memorize for the exam because it will be on it:
round(),ceil(), and floor() take floats and return "integer equivalents". ceil() and floor() actually return a double.

Good Luck!

[Jay Pawar]

Originally posted by Chitra AP:
Hi All,

K&B book says ceil(), floor() and round() all return integer equivalent floating-point numbers. But the following code prints

System.out.println(Math.round(1.1)); //prints 1
System.out.println(Math.ceil(1.1)); // prints 2.0

The first line should print 1.0, correct? Thanks.

Chitra,
Math.round() returns int or long depending on the argument passed to it. i.e
Math.round(double d) will return long whereas Math.round(float f) would return you int data type.
Math.ceil(double d) always returns double.

Check this link for Math functions.
Hope that helps...

[amit taneja]

can any body pls explain some trick to find round() of negative no..

sometimes i got confuse

i m good for solving positive ones... like add .5 and if no. after decimal is =>.5 then ciel() else floor()

tell something about negative no. and some eg.

thanx

[Whitney M. Davis]

I defer to Shweta...
[ June 09, 2005: Message edited by: Whitney M. Davis ]

[amit taneja]

Originally posted by Whitney M. Davis:
Hi Amit,

So the rule for round() is you add 0.5 to the argument and then cut off whatever is after the decimal. So if you start with round(3.2), you add 0.5 and get 3.7, then cut off everything after the decimal to get 3.

ya... i got it simple...
take that wise

if in negative no. is =<.5 do ciel() else floor

[Shweta R Dhaneshwar]

Hi Whitney ,

So when you add 0.5 to round(-3.2) you intuitively think you should get -3.7 but you really get -2.7 and the answer will be -2. Confusing! And it'll be on the test!

I think you are wrong here.round(-3.2) is not -2 but it is -3.

Amit,
Irrespective of the number being positive or negative you have to add 0.5 to the number and then do Math.floor().