random.cpp

Vc++中的舎伍德算法实现线性时间选择算法

#include "Random.h"
#include <time.h> 

RandomNumber::RandomNumber(unsigned long s) 
{ 
	if(s==0) 
		randseed = time(0); 
	else 
		randseed = s; 
} 
unsigned short RandomNumber::Random(unsigned long n) 
{ 
	randseed=multiplier*randseed+adder; 
	return (unsigned short)((randseed>>16)%n); 
} 

double RandomNumber::fRandom(void) 
{ 
	return Random(maxshort)/double(maxshort); 
}