Class Random
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§3.7 Class Random
public class java.util.Random
extends java.lang.Object (I-§1.12)
{
// Constructors
public Random(); §3.7.1
public Random(long seed); §3.7.2
// Methods
public double nextDouble(); §3.7.3
public float nextFloat(); §3.7.4
public double nextGaussian(); §3.7.5
public int nextInt(); §3.7.6
public long nextLong(); §3.7.7
public void setSeed(long seed); §3.7.8
}
An instance of this class is used to generate a stream of pseudo-random numbers. The
class uses a 48-bit seed, which is modified using a linear congruential formula. See
Donald Knuth, The Art of Computer Programming, Volume 2, Section 3.2.1.
If two instances of Random are created with the same seed, and the same sequence of
method calls is made for each, they will generate and return identical sequences of numbers.
Many applications will find the random method (I-§1.10.26) in class Math simpler to use.
Random
public Random()
- Creates a new random number generator. Its seed is initialized to a value
based on the current time (I-§1.18.5).
Random
public Random(long seed)
- Creates a new random number generator using a single long seed.
- Parameters:
seed
- the initial seed
- See Also:
- setSeed (I-§3.7.8).
nextDouble
public double nextDouble()
- Returns:
- the next pseudorandom, uniformally distributed double value
between 0.0 and 1.0 from this random number generator's sequence.
nextFloat
public float nextFloat()
- Returns:
- the next pseudorandom, uniformally distributed float value
between 0.0 and 1.0 from this random number generator's sequence.
nextGaussian
public double nextGaussian()
- Returns:
- the next pseudorandom, Gaussian ("normally") distributed double
value with mean 0.0 and standard deviation 1.0 from this random
number generator's sequence.
nextInt
public int nextInt()
- Returns:
- the next pseudorandom, uniformally distributed int value from this
random number generator's sequence.
nextLong
public long nextLong()
- Returns:
- the nextpseudorandom, uniformally distributed long value from this
random number generator's sequence.