Pi day code

pi-estimato.cpp

#include <iostream>
#include <iomanip>
#include <cmath>
#include <random>
#include <tuple>
#include <functional>
const double PI=3.14159265359;
bool within_circle(double radius,double x,double y){
    return std::hypot(x,y)<radius;
}

template<typename Y> double proportion_succeded(long n,std::function<bool(Y)>& p, std::function<Y()>& g){
    double dn=n;
    double succ=0;
    for(size_t i=0;i<n;i++)
        if(p(g()))
            succ+=1/dn;
    return succ;
}
void calculate_pi(int min_sample_exp,int max_sample_exp,int min_radius_exp,int max_radius_exp){
    double radius=1;
    long samples=1;
    std::default_random_engine en;
    std::uniform_real_distribution<double> gen(0.0,radius);
    std::function<bool(std::tuple<double,double>)> pred=
            [&](std::tuple<double,double> p){return within_circle(radius,std::get<0>(p),std::get<1>(p));};
    std::function<std::tuple<double,double>()> point_gen=
            [&]()->std::tuple<double,double>{return std::make_tuple<double,double>(gen(en),gen(en));};
    for(int m=min_sample_exp;m<max_sample_exp;m++)
        std::cout<<std::setw(5)m<<"\t";
    std::cout<<"\n";
    std::vector<std::future<double>>
    for(int n=min_radius_exp;n<=max_radius_exp;n++){
        //update the generator's maximum
        radius=std::pow(10,n);
        gen=std::uniform_real_distribution<double>(0,radius);
        for(int m=min_sample_exp;m<=max_sample_exp;m++){
            samples=std::pow(10,m);
            //run the samples
            double temp=proportion_succeded(samples,
                                            pred,
                                            point_gen)*4;
            //show the absolute difference between the calculated value and PI
            std::cout<<std::setw(5)<<std::abs(temp-PI)<<std::setw(5)<<"\t";
        }
    std::cout<<"\n"<<std::flush;
    }
}
int main(){
    calculate_pi(0,9,0,7);
    return 0;
}