poisson.cpp

用C语言实现的泊松

       #include <stdio.h>
#include <stdlib.h>
#include <math.h>
int z[100000];
void save()
{FILE*fp3;
 int i;
 if((fp3=fopen("shuju3.txt","w"))==NULL)
  {printf("cannot open file shuju3.txt\n");
    return;
   }
  for(i=0;i<100000;i++)
   {
     fprintf(fp3,"%d  ",z[i]);
   }
    fclose(fp3);
}
int poi(double t)
{ int i=0;
  double b=1,a,u;
  a=exp(-t);
  while(1)
   {u=(double)rand()/(double)RAND_MAX;
    b=b*u;
    if(b<a) break;
    i++;
   }
   return (i);
}
main()
{ int k;
  for(k=1;k<100000;k++)
  z[k]=poi(0.2);
  save();
}