Random Class Reference

A random number generator. More...

Public Member Functions
	Random (int64 seedValue) noexcept
	Creates a Random object based on a seed value.
	Random ()
	Creates a Random object using a random seed value.
int	nextInt () noexcept
	Returns the next random 32 bit integer.
int	nextInt (int maxValue) noexcept
	Returns the next random number, limited to a given range.
int	nextInt (Range< int > range) noexcept
	Returns the next random number, limited to a given range.
int64	nextInt64 () noexcept
	Returns the next 64-bit random number.
float	nextFloat () noexcept
	Returns the next random floating-point number.
double	nextDouble () noexcept
	Returns the next random floating-point number.
bool	nextBool () noexcept
	Returns the next random boolean value.
BigInteger	nextLargeNumber (const BigInteger &maximumValue)
	Returns a BigInteger containing a random number.
void	fillBitsRandomly (void *bufferToFill, size_t sizeInBytes)
	Fills a block of memory with random values.
void	fillBitsRandomly (BigInteger &arrayToChange, int startBit, int numBits)
	Sets a range of bits in a BigInteger to random values.
void	setSeed (int64 newSeed) noexcept
	Resets this Random object to a given seed value.
int64	getSeed () const noexcept
	Returns the RNG's current seed.
void	combineSeed (int64 seedValue) noexcept
	Merges this object's seed with another value.
void	setSeedRandomly ()
	Reseeds this generator using a value generated from various semi-random system properties like the current time, etc.

Static Public Member Functions
static Random &	getSystemRandom () noexcept
	The overhead of creating a new Random object is fairly small, but if you want to avoid it, you can call this method to get a global shared Random object.

Detailed Description

A random number generator.

You can create a Random object and use it to generate a sequence of random numbers.

Constructor & Destructor Documentation

Random() [1/2]

Random::Random ( int64 seedValue )

explicitnoexcept

Creates a Random object based on a seed value.

For a given seed value, the subsequent numbers generated by this object will be predictable, so a good idea is to set this value based on the time, e.g.

new Random (Time::currentTimeMillis())

Referenced by getSystemRandom().

Random() [2/2]

Random::Random

(

)

Creates a Random object using a random seed value.

Internally, this calls setSeedRandomly() to randomise the seed.

Member Function Documentation

nextInt() [1/3]

int Random::nextInt ( )

noexcept

Returns the next random 32 bit integer.

Returns

a random integer from the full range 0x80000000 to 0x7fffffff

Referenced by midi_ci::DeviceOptions::makeProductInstanceId(), midi_ci::MUID::makeRandom(), nextInt(), and nextInt().

nextInt() [2/3]

int Random::nextInt ( int maxValue )

noexcept

Returns the next random number, limited to a given range.

The maxValue parameter may not be negative, or zero.

Returns

a random integer between 0 (inclusive) and maxValue (exclusive).

References nextInt().

nextInt() [3/3]

int Random::nextInt ( Range< int > range )

noexcept

Returns the next random number, limited to a given range.

Returns

a random integer between the range start (inclusive) and its end (exclusive).

References nextInt().

nextInt64()

int64 Random::nextInt64 ( )

noexcept

Returns the next 64-bit random number.

Returns

a random integer from the full range 0x8000000000000000 to 0x7fffffffffffffff

References nextInt64().

Referenced by nextInt64().

nextFloat()

float Random::nextFloat ( )

noexcept

Returns the next random floating-point number.

Returns

a random value in the range 0 (inclusive) to 1.0 (exclusive)

References nextFloat().

Referenced by nextFloat().

nextDouble()

double Random::nextDouble ( )

noexcept

Returns the next random floating-point number.

Returns

a random value in the range 0 (inclusive) to 1.0 (exclusive)

References nextDouble().

Referenced by nextDouble().

nextBool()

bool Random::nextBool ( )

noexcept

Returns the next random boolean value.

References nextBool().

Referenced by nextBool().

nextLargeNumber()

BigInteger Random::nextLargeNumber

(

const BigInteger &

maximumValue

)

Returns a BigInteger containing a random number.

Returns

a random value in the range 0 to (maximumValue - 1).

References nextLargeNumber().

Referenced by nextLargeNumber().

fillBitsRandomly() [1/2]

void Random::fillBitsRandomly	(	void *	bufferToFill,
		size_t	sizeInBytes )

Fills a block of memory with random values.

References fillBitsRandomly().

Referenced by fillBitsRandomly(), and fillBitsRandomly().

fillBitsRandomly() [2/2]

void Random::fillBitsRandomly	(	BigInteger &	arrayToChange,
		int	startBit,
		int	numBits )

Sets a range of bits in a BigInteger to random values.

References fillBitsRandomly().

setSeed()

void Random::setSeed ( int64 newSeed )

noexcept

Resets this Random object to a given seed value.

References setSeed().

Referenced by setSeed().

getSeed()

int64 Random::getSeed ( ) const

noexcept

Returns the RNG's current seed.

References getSeed().

Referenced by getSeed().

combineSeed()

void Random::combineSeed ( int64 seedValue )

noexcept

Merges this object's seed with another value.

This sets the seed to be a value created by combining the current seed and this new value.

setSeedRandomly()

void Random::setSeedRandomly

(

)

Reseeds this generator using a value generated from various semi-random system properties like the current time, etc.

Because this function convolves the time with the last seed value, calling it repeatedly will increase the randomness of the final result.

getSystemRandom()

static Random & Random::getSystemRandom ( )

staticnoexcept

The overhead of creating a new Random object is fairly small, but if you want to avoid it, you can call this method to get a global shared Random object.

Note this will return a different object per thread it's accessed from, making it thread safe. However, it's therefore important not store a reference to this object that will later be accessed from other threads.

References Random().