KRandomSequence Class Reference

#include <KRandomSequence>

Public Member Functions
	KRandomSequence (long lngSeed=0)
	KRandomSequence (const KRandomSequence &a)
virtual	~KRandomSequence ()
bool	getBool ()
double	getDouble ()
unsigned long	getLong (unsigned long max)
void	modulate (int i)
KRandomSequence &	operator= (const KRandomSequence &a)
template<typename T >
void	randomize (QList< T > &list)
void	setSeed (long lngSeed=0)

Detailed Description

A class to create a pseudo-random sequence.

Given a seed number, this class will produce a sequence of pseudo-random numbers. This would typically be used in applications like games.

In general, you should instantiate a KRandomSequence object and pass along your seed number in the constructor. From then on, simply call getDouble or getLong to obtain the next number in the sequence.

Author

Sean Harmer sh@as.nosp@m.tro..nosp@m.keele.nosp@m..ac..nosp@m.uk

Definition at line 40 of file krandomsequence.h.

Constructor & Destructor Documentation

KRandomSequence::KRandomSequence ( long  lngSeed = 0 )

explicit

Creates a pseudo-random sequence based on the seed lngSeed.

A Pseudo-random sequence is different for each seed but can be reproduced by starting the sequence with the same seed.

If you need a single value which needs to be unpredictable, you need to use KRandom::random() instead.

Parameters

lngSeed

Seed to initialize the sequence with. If lngSeed is 0, the sequence is initialized with a value from KRandom::random().

Definition at line 42 of file krandomsequence.cpp.

KRandomSequence::~KRandomSequence ( )

virtual

Standard destructor.

Definition at line 48 of file krandomsequence.cpp.

KRandomSequence::KRandomSequence

(

const KRandomSequence &

a

)

Copy constructor.

Definition at line 53 of file krandomsequence.cpp.

Member Function Documentation

bool KRandomSequence::getBool

(

)

Get a boolean from the pseudo-random sequence.

Returns

a boolean which is either true or false

Definition at line 215 of file krandomsequence.cpp.

double KRandomSequence::getDouble

(

)

Get the next number from the pseudo-random sequence.

Returns

a pseudo-random double value between [0,1)

Definition at line 187 of file krandomsequence.cpp.

unsigned long KRandomSequence::getLong

(

unsigned long

max

)

Get the next number from the pseudo-random sequence.

Returns

a pseudo-random integer value between [0, max) with 0 <= max < 1.000.000

Definition at line 207 of file krandomsequence.cpp.

void KRandomSequence::modulate

(

int

i

)

Modulate the random sequence.

If S(i) is the sequence of numbers that will follow given the current state after calling modulate(i), then S(i) != S(j) for i != j and S(i) == S(j) for i == j.

This can be useful in game situation where "undo" restores the state of the random sequence. If the game modulates the random sequence with the move chosen by the player, the random sequence will be identical whenever the player "redo"-s his or hers original move, but different when the player chooses another move.

With this scenario "undo" can no longer be used to repeat a certain move over and over again until the computer reacts with a favorable response or to predict the response for a certain move based on the response to another move.

Parameters

i	the sequence identified

Definition at line 170 of file krandomsequence.cpp.

KRandomSequence & KRandomSequence::operator=

(

const KRandomSequence &

a

)

Assignment.

Definition at line 58 of file krandomsequence.cpp.

template<typename T >

void KRandomSequence::randomize ( QList< T > &  list )

inline

Put a list in random order.

Since KDE 4.11, this function uses a more efficient algorithm (Fisher-Yates). Therefore, the order of the items in the randomized list is different from the one in earlier versions if the same seed value is used for the random sequence.

Parameters

list	the list whose order will be modified

Note

modifies the list in place

Definition at line 112 of file krandomsequence.h.

void KRandomSequence::setSeed

(

long

lngSeed = 0

)

Restart the sequence based on lngSeed.

Parameters

lngSeed

Seed to initialize the sequence with. If lngSeed is 0, the sequence is initialized with a value from KRandom::random().

Definition at line 71 of file krandomsequence.cpp.

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The documentation for this class was generated from the following files:

• krandomsequence.h
• krandomsequence.cpp