Java Reference
In-Depth Information
4-1. Rounding Float and Double Values
to Integers
Problem
You need to be able to round floating-point numbers or
doubles
in your application
to
Integer
values.
Solution
Use one of the
java.lang.Math round()
methods to round the number into the
format you require. The
Math
class has two methods that can be used for rounding
floating-point numbers or
Double
values. The following code demonstrates how to
use each of these methods:
public static int roundFloatToInt(float myFloat){
return Math.round(myFloat);
}
public static long roundDoubleToLong(double myDouble){
return Math.round(myDouble);
}
The first method,
roundFloatToInt()
, accepts a floating-point number and
uses the
java.lang.Math
class to round that number to an
Integer
. The second
method,
roundDoubleToLong()
, accepts a
Double
value and uses the
java.lang.Math
class to round that
Double
to a
Long
.
How It Works
The
java.lang.Math
class contains plenty of helper methods to make our lives
easier when working with numbers. The
round()
methods are no exception as they
can be used to easily round floating-point or double values. One version of the
java.lang.Math round()
method accepts a float as an argument. It will round
the float to the closest
int
value, with ties rounding up. If the argument is
NaN
, then a
