random.h

A Mersenne Twister Class

#if !defined(RANDOM_GENERATOR_INCLUDED)
#define RANDOM_GENERATOR_INCLUDED

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <windows.h>
#include <math.h>

const   int	N = 624;		// Replaced the #defines for these with const values - DHL
const   int M = 397;
const   unsigned int K = 0x9908B0DFU;
const   unsigned int DEFAULT_SEED = 4357;

#define hiBit(u)       ((u) & 0x80000000U)   // mask all but highest   bit of u
#define loBit(u)       ((u) & 0x00000001U)   // mask all but lowest    bit of u
#define loBits(u)      ((u) & 0x7FFFFFFFU)   // mask     the highest   bit of u
#define mixBits(u, v)  (hiBit(u)|loBits(v))  // move hi bit of u to hi bit of v

class CRandomMT
{
	ULONG	state[N+1];     // state vector + 1 extra to not violate ANSI C
	ULONG  *next;			// next random value is computed from here
	int     left;			// can *next++ this many times before reloading
	UINT	seedValue;		// Added so that setting a seed actually maintains 
							// that seed when a ReloadMT takes place.
	
public:
				CRandomMT();
				CRandomMT(ULONG _seed);
				~CRandomMT(){};
	void		SeedMT(ULONG seed);


inline ULONG CRandomMT::RandomMT(void)
{
    ULONG y;

    if(--left < 0)
        return(ReloadMT());

    y  = *next++;
    y ^= (y >> 11);
    y ^= (y <<  7) & 0x9D2C5680U;
    y ^= (y << 15) & 0xEFC60000U;
    return(y ^ (y >> 18));
}


inline int	RandomMax(int max)
{
	return(((int)RandomMT()%max));
}


inline int RandomRange(int lo, int hi)
{
	// Changed thanks to mgearman's message
	return (abs((int)RandomMT() % (hi - lo + 1)) + lo);
}

inline int RollDice(int face, int number_of_dice)
{
	int roll = 0;
	for(int loop=0; loop < number_of_dice; loop++)
	{
		roll += (RandomRange(1,face));
	}
	return roll;
}

inline int CRandomMT::HeadsOrTails()
{
	return((RandomMT()) % 2);
}

inline	int		D6(int die_count)	{ return RollDice(6,die_count); }
inline	int		D8(int die_count)	{ return RollDice(8,die_count); }
inline	int		D10(int die_count)	{ return RollDice(10,die_count); }
inline	int		D12(int die_count)	{ return RollDice(12,die_count); }
inline	int		D20(int die_count)	{ return RollDice(20,die_count); }
inline	int		D25(int die_count)	{ return RollDice(25,die_count); }

private:
	ULONG	ReloadMT(void);

};

#endif //RANDOM_GENERATOR_INCLUDED

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