format_test.cpp

/**********************\
Name:     format_test.cpp
Author:   Gabriel Espinoza <virtuoso.sdc@gmail.com>
License:  MIT
Desc:     string concatenation and output test benchmark
*/

//!!!! C++ 2020 required

#include <iostream>
#include <chrono>
#include <functional>
#include <string_view>
#include <format>
#include <strstream>

using namespace std;
using namespace std::chrono;

auto run1Mtimes(string_view s,function<void()> f)
{
    auto start = system_clock::now();
    for(int i = 0 ; i < 1'000; ++i)
    {
        f();
    }
    auto d = duration_cast<microseconds>(system_clock::now() - start).count();
    return format("function {} took {} us to run\n",s,d);
}


int main()
{
    ios::sync_with_stdio(false);
    string_view s {"output to cout"};
    double d = 1.6;
    int i = 123;
    vector<string> v;
    v.push_back(run1Mtimes("format",[&](){ cout << format("{} {} {}\n",s,d,i);}));

    v.push_back(run1Mtimes("ostringstream",[&](){
        ostringstream os;
        os << s << " " << d << " " << i << endl;
        cout << os.str();
    }));

    v.push_back(run1Mtimes("+",[&](){ cout << string() + s.data() + " " + to_string(d) + " " + to_string(i) +"\n";}));

    v.push_back(run1Mtimes("+=",[&](){
        string str;
        str +=  s.data();
        str +=  " ";
        str +=  to_string(d);
        str +=  " ";
        str +=  to_string(i);
        str +=  "\n";
        cout << str;
    }));

    v.push_back(run1Mtimes("printf",[&](){
        printf("%s %f %i\n",s.data(),d,i);
    }));

    v.push_back(run1Mtimes("cout",[&](){ cout << s << " " << d << " " << i << endl;}));

    ranges::copy(v,ostream_iterator<string>(cerr,"\n"));
    return 0;

}