distribuzione distanza

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


typedef unsigned long long int RANDOM_TYPE;
RANDOM_TYPE a, b, m, seed, randomNumber;

struct{
double x,y,z;
}p;

double distanza(double x1, double x2, double x3);
double distribuzione(double fstoredistanzarandomnumber[], int fpassi, int fn_bin);

int main(){
double r, xt2, arraybin[10], distanzatot, media, bin=10000;
int position, i, c,g,passi=100,n_bin=70;
double storedistanzarandomnumber[passi];

i=0; media=0;
p.x=0; p.y=0; p.z=0;
position=0;
i=0;
a=16807;
m=2147483647;
seed=222;
randomNumber=seed;
FILE *fp;
fp=fopen("casuale_3D.dat","w+");
    for(i=1; i<passi; i++){
        fprintf(fp,"%d %lf %lf %lf %Lu \n", i,p.x,p.y,p.z,randomNumber);
        randomNumber=(a*randomNumber)%m;
        r=(double)randomNumber/(double)m;
            if(r<(1/6.)){
            p.z+=1;
            }
            else if (r<(2/6.)){
            p.z-=1;
            }
            else if (r<(3/6.)){
            p.x+=1;
            }
            else if (r<(4/6.)){
            p.x-=1;
            }
            else if (r<(5/6.)){
            p.y+=1;
            }
            else if (r<1){
            p.y-=1;
            }
        storedistanzarandomnumber[i]=distanza(p.x,p.y,p.z);
    }
FILE *ff;
ff=fopen("casuale_distanza.dat","w+");
    for(i=1; i<passi; i++){
        fprintf(ff,"%lf \n",*(storedistanzarandomnumber+i));
    }
distribuzione(storedistanzarandomnumber, passi, n_bin);

}


double distanza(double x1,double x2,double x3){
    double dist;
    dist=sqrt(x1*x1+x2*x2+x3*x3);
    return dist;
}

////////////////////////////////////////////////////////////////////////////////////////////////


double distribuzione(double fstoredistanzarandomnumber[], int fpassi, int fn_bin){
FILE *fq;
int i, determinobin;
double max, arraybin[fn_bin], grandezzabin;
//determino distanza max/////////
    for(i=1; i<fpassi; i++){
        if(max<fstoredistanzarandomnumber[i]){max=fstoredistanzarandomnumber[i];}
    }
    printf("il massimo è %lf",max);

grandezzabin=max/fn_bin;//determino grandezza bin
//riempio bin/////////
i=0;
    for(i=1; i<fpassi; i++){
            determinobin=fstoredistanzarandomnumber[i]/grandezzabin;
            printf(" %d*bin = %d \n",i,determinobin);
            arraybin[determinobin]+=1;
    }
//scrivo distribuzione///////////
fq=fopen("casuale_distr_dista.dat","w+");
i=0;
    for(i=1; i<fpassi; i++){
        if(arraybin[i]!=0){fprintf(fq,"%d %lf \n",i,arraybin[i]);}
    }
system("echo 'plot \"casuale_distr_dista.dat\" u 1:2 with lines'|gnuplot -persist");
system("echo 'splot \"casuale_3D.dat\" u 2:3:4 with lines'|gnuplot -persist");

}