#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define MAX_PARTICLES 100000

main()
{
  unsigned int seed;
  int nran;
  int i,j;
  int istep,nstep;
  int im,m[100];
  float a1;
  float h;
  float x[MAX_PARTICLES];
  double step;

  FILE *output;
  
  output = fopen("nm.dat","w");


  printf("Input: seed\n");
  scanf("%u", &seed);
/*  printf("seed=%u\n",seed); */
  printf("Number of particles:\n");
  scanf("%u", &nran);
  printf("Input: Number of steps:\n");
  scanf("%u", &nstep);

  srand(seed);

  for(i=0; i < 50; i++){
    m[i]=0;
  }

  h=1.0;

  for(i=0; i < nran; i++){
    x[i]=0.0;
    for(istep=0; istep < nstep; istep++){
      j=rand();
      a1=j/(RAND_MAX+1.0);
      /*    printf("a1=%.5f\n",a1); */
      if(a1<0.5)
	x[i]=x[i]-h;
      else
	x[i]=x[i]+h;
    }

/*    printf("x=%.5f\n",x[i]); */
    im=(int) (5.0*fabs(x[i]))/sqrt((double) nstep);
/*    printf("x=%f\tim=%d\n",x[i],im); */
    m[im]=m[im]+1;

  } 

  for(im=0; im<20; im++){
    printf("%.2f  %d\n",im/5.0,m[im]);
    fprintf(output, "%.2f  %d\n",im/5.0,m[im]);
  }

  return;
}