normal.cpp

用C语言实现的泊松

   # include<math.h>
# include<stdio.h>
# include <stdlib.h>
double z[100000];
void save()
{FILE*fp1;
 int i;
 if((fp1=fopen("shuju1.txt","w"))==NULL)
  {printf("cannot open file shuju1.txt\n");
    return;
   }
  for(i=0;i<100000;i++)
   {
     fprintf(fp1,"%6.4f  ",z[i]);
   }
    fclose(fp1);
}
double  N(double mean,double var)
{
  double u1,u2,v1,v2,w,x,s,y;
  do
  { u1=(double)rand()/(double)RAND_MAX;
    u2=(double)rand()/(double)RAND_MAX;
	v1=2*u1-1;
	v2=2*u2-1;
	w=v1*v1+v2*v2;
  } while(w>1);
  y=sqrt((-2*log (w))/w);
  x=v1*y;
  s=mean+var*x;
  return(s);
}
 void main()
 {int i;
 for(i=0;i<100000;i++)
   z[i]=N(0,1);
  save();
 }