Java Reference
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Display 5.6 Some Methods in the Class Math (part 2 of 2)
public static long round( double argument)
public static int round( float argument)
Rounds its argument .
EXAMPLE
Math.round(3.2) returns 3 ; Math.round(3.6) returns 4 .
public static double ceil( double argument)
Returns the smallest whole number greater than or equal to the argument .
EXAMPLE
Math.ceil(3.2) and Math.ceil(3.9) both return 4.0 .
public static double floor( double argument)
Returns the largest whole number less than or equal to the argument .
EXAMPLE
Math.floor(3.2) and Math.floor(3.9) both return 3.0 .
public static double sqrt( double argument)
Returns the square root of its argument .
EXAMPLE
Math.sqrt(4) returns 2.0 .
The class Math has three similar methods named round , floor , and ceil . Some of
these return a value of type double , but they all return a value that is intuitively a
whole number that is close to the value of their arguments. The method round rounds
a number to the nearest whole number, and (if the argument is a double ) it returns
that whole number as a value of type long. If you want that whole number as a value
of type int , you must use a type cast as in the following:
double exact = 7.56;
int roundedValue = ( int )Math.round(exact);
You cannot assign a long value to a variable of type int , even if it is a value such as 8 ,
which could just as well have been an int . A value such as 8 can be of type either int
or long (or even of type short or byte ) depending on how it was created.
 
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