#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<time.h>
#define MAXTETA M_PI/2
double frominput(double min,double max);
double randreal(double min, double max);

int main(){
srand48(time(0));

double l,d,n,teta,x,i,S,pi;

    printf("Dammi l ");
    l=frominput(0,5);
    printf("Dammi d ");
    d=frominput(0,5);
    printf("Dammi n ");
    n=frominput(0,10000);

    printf("l %lf,d %lf,n %lf",l,d,n);

    for(i=0;i<1000;i++){
            for(i=0;i<n;i++){
                teta=randreal(0,MAXTETA);
                x=randreal(0,d/2);
                       if(x<(l/2)*sin(teta)){
                                        S+=1;
                                            }
                            }
                 printf("\nS vale %lf \n",&S);
                 pi=(2*l*n)/S*d;
                 printf("pi vale %lf\n",pi);

                FILE*output;
                output=fopen("pi.dat","w");
                    if(output){
                            fprintf(output,"vale %lf\n",pi);
                              }

                        }
 return 0;
}




double frominput(double min,double max){
double x,l=0,d=0;

do{
    printf("compreso fra [%lf,%lf]\n",min,max);
    scanf("%lf",&x);
    }while(x<min || x>max);

return x;
}

double randreal(double min, double max){
    double range = (max - min);
    double denom = RAND_MAX / range;

    return min + (lrand48() / denom);

// solo a=min compreso randmax+1.solo b=max compreso randmax+1. e lrand+1. nessuno compreso rand+2. lrand+1.
}