probability calculator

a.cpp

#include <iostream>
#include <cstdlib>
#include <vector>

using namespace std;

double rand_double()
{
    return std::rand()/(double)RAND_MAX;
}

int occurence_random_from_vector(vector<double> d)
{
    double randnow=rand_double();
    int i=0;
    for (i=0;i<d.size();i++)
    {
        if (randnow>d[i]) return i;
    }
    return i; //valami relative nagy szam lett, a veget levagjuk


}

int main()
{
    int observation_number_of_occurences=2;
    int observation_number_of_time_units=60*2;
    int hypot_number_of_time_units=10;
    double hypot_probability_of_zero_occurences;

    int good_obs_num=0;
    int good_obs_zero_occ_num=0;

    while (true)
    {
        double random_probability = rand_double();
        std::vector<double> d={random_probability};
        double last_elem=random_probability;
        for (int i=0;i<observation_number_of_occurences;i++)
        {
            last_elem*=random_probability;
            d.push_back(last_elem);
        }
        int sum=0;
        for(int i=0;i<observation_number_of_time_units;i++)
        {
            sum+=occurence_random_from_vector(d);
            if (sum>observation_number_of_occurences) break;
        }
        if (sum==observation_number_of_occurences)
        {
            good_obs_num++;
            int sum_hypot=0;
            int sum2=0;
            for(int i=0;i<hypot_number_of_time_units;i++)
            {
                sum2+=occurence_random_from_vector(d);
            }
            if (sum2==0)
            {
                good_obs_zero_occ_num++;

                //std::cout<<ratio<<"\n";
            }
              double ratio=good_obs_zero_occ_num/(double)good_obs_num;
                printf("%f  %f %d %d %d\n",ratio,random_probability,good_obs_zero_occ_num,good_obs_num,sum2);
            //}



        }



    }




}