Java Reference
In-Depth Information
For example,
Math.ceil(
2.1
)
returns
4.0
Math.ceil(
2.0
)
returns
2.0
Math.ceil(
-2.0
)
returns
-2.0
Math.ceil(
-2.1
)
returns
-2.0
Math.floor(
2.1
)
returns
2.0
Math.floor(
2.0
)
returns
2.0
Math.floor(
-2.0
)
returns
-2.0
Math.floor(
-2.1
)
returns
-4.0
Math.rint(
2.1
)
returns
2.0
Math.rint(
-2.0
)
returns
-2.0
Math.rint(
-2.1
)
returns
-2.0
Math.rint(
2.5
)
returns
2.0
Math.rint(
4.5
)
returns
4.0
Math.rint(
-2.5
)
returns
-2.0
Math.round(
2.6f
)
returns
3
// Returns int
Math.round(
2.0
)
returns
2
// Returns long
Math.round(
-2.0f
)
returns
-2
// Returns int
Math.round(
-2.6
)
returns
-3
// Returns long
Math.round(
-2.4
)
returns
-2
// Returns long
4.2.4 The
min
,
max
, and
abs
Methods
The
min
and
max
methods return the minimum and maximum numbers of two numbers (
int
,
long
,
float
, or
double
). For example,
max(4.4, 5.0)
returns
5.0
, and
min(3, 2)
returns
2
.
The
abs
method returns the absolute value of the number (
int
,
long
,
float
, or
double
).
For example,
Math.max(
2
,
3
)
returns
3
Math.max(
2.5
,
3
)
returns
4.0
Math.min(
2.5
,
4.6
)
returns
2.5
Math.abs(
-2
)
returns
2
Math.abs(
-2.1
)
returns
2.1
4.2.5 The
random
Method
You have used the
random()
method in the preceding chapter. This method generates a ran-
dom
double
value greater than or equal to 0.0 and less than 1.0 (
0 <= Math.random() <
1.0
). You can use it to write a simple expression to generate random numbers in any range.
For example,
Returns a random integer
between
0
and
9
.
(
int
)(Math.random() *
10
)
Returns a random integer
between
50
and
99
.
50
+ (
int
)(Math.random() *
50
)
In general,
Returns a random number between
a
and
a + b
, excluding
a + b
.
a + Math.random() * b
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