// Written by fede.tft, public domain

#include <iostream>
#include <chrono>
#include <algorithm>
#include <limits>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

using namespace std;
using namespace std::chrono;

const int n=100000000; //Number of iterations

int main()
{
    int fd=open("/dev/null",O_RDWR);
    if(fd<0) return 1;
    long long minVal=numeric_limits<long long>::max(), avgVal=0;
    for(int i=0;i<n;i++)
    {
        char c=0;
        auto t1=high_resolution_clock::now();
        if(write(fd,&c,1)!=1) return 1;
        auto t2=high_resolution_clock::now();
        long long t=duration_cast<duration<double>>(t2-t1).count()*1e9;
        minVal=min(minVal,t);
        avgVal+=t;
    }
    close(fd);
    avgVal/=n;
    cout<<"min="<<minVal<<" ns\navg="<<avgVal<<" ns\n";
    return 0;
}