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教你怎么用C++产各种各样的随机数

#define IA 16807
#define IM 2147483647
#define AM (1.0/IM)
#define IQ 127773
#define IR 2836
#define NTAB 32
#define NDIV (1+(IM-1)/NTAB)
#define EPS 1.2e-7
#define RNMX (1.0-EPS)
class GaussianRN{
 public:
  long idum;
  GaussianRN(long didum){
    idum = didum;
  }
  virtual ~GaussianRN(){
    
  }
  double GaussianRN::gasdev(){
    return gasdev(&idum);
  }
  double GaussianRN::ran1(long *idum)
    {
      int j;
      long k;
      static long iy=0;
      static long iv[NTAB];
      double temp;
      
      if (*idum <= 0 || !iy) {
	if (-(*idum) < 1) *idum=1;
	else *idum = -(*idum);
	for (j=NTAB+7;j>=0;j--) {
	  k=(*idum)/IQ;
	  *idum=IA*(*idum-k*IQ)-IR*k;
	  if (*idum < 0) *idum += IM;
	  if (j < NTAB) iv[j] = *idum;
	}
	iy=iv[0];
      }
      k=(*idum)/IQ;
      *idum=IA*(*idum-k*IQ)-IR*k;
      if (*idum < 0) *idum += IM;
      j=iy/NDIV;
      iy=iv[j];
      iv[j] = *idum;
      if ((temp=AM*iy) > RNMX) return RNMX;
      else return temp;
    }
double GaussianRN::gasdev(long *idum)
  {
    
    static int iset=0;
    static double gset;
    double fac,rsq,v1,v2;
    
    if  (iset == 0) {
      do {
	v1=2.0*ran1(idum)-1.0;
	v2=2.0*ran1(idum)-1.0;
	rsq=v1*v1+v2*v2;
      } while (rsq >= 1.0 || rsq == 0.0);
      fac=sqrt(-2.0*log(rsq)/rsq);
      gset=v1*fac;
      iset=1;
      return v2*fac;
    } else {
      iset=0;
      return gset;
    }
  }
 private:
 GaussianRN(const GaussianRN& rhs);
  const GaussianRN &operator=(const GaussianRN& rhs);

 
};
#undef IA
#undef IM
#undef AM
#undef IQ
#undef IR
#undef NTAB
#undef NDIV
#undef EPS
#undef RNMX