casuale 3d con stampa

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

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

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

int main(){
double r, xt2, arraybin[10], distanzatot, media, bin=10000;
int position, i, c,g,passi=10000;
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 *ff;
FILE *fp;
ff=fopen("casuale.dat","w+");
    for(i=1; i<passi; i++){
        randomNumber=(a*randomNumber)%m;
        fprintf(ff,"%d %lf %lf %lf %Lu \n", i,p.x,p.y,p.z,randomNumber);
        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;
            }

    }
fp=fopen("dati_png.gnu","w");
fprintf(fp, " splot 'casuale.dat' u 2:3:4 \n set xlabel 'x' \n set ylabel 'y' \n set zlabel 'z'\n set term png \n set output 'casuale.png' \n replot \n  \n ");
fclose(fp);
system("gnuplot dati_png.gnu");
fp=fopen("dati_ps.gnu","w");
fprintf(fp, " plot 'casuale.dat' u 2:3:4 \n set xlabel 'x' \n set ylabel 'y' \n set zlabel 'z' \n set term post col \n set output 'eull.ps' \n replot \n  \n ");
fclose(fp);
system("gnuplot dati_ps.gnu");
system("rm dati_ps.gnu");
system("rm dati_png.gnu");
system("gnuplot>splot 'casuale.dat' u 2:3:4");
}