/******************************************************************************
 * This program demonstrates a function to compute π
 * 
 * Copyright © 2017 Richard Lesh.  All rights reserved.
 *****************************************************************************/

#include <clocale>
#include <cmath>
#include <codecvt>
#include <fmt/format.h>
#include <fmt/xchar.h>
#include <iostream>
#include <string>

std::locale utf8loc(std::locale(), new std::codecvt_utf8<wchar_t>);
using namespace std;

double calcpi() noexcept {
    return 2.0 * acos(0.0);
}

int main(int argc, char **argv) {
    setlocale(LC_ALL, "en_US.UTF-8");
    wcout.imbue(utf8loc);
    wcin.imbue(utf8loc);

    double const PI = calcpi();
    wcout << fmt::format(L"PI: {0:.15f}", PI) << endl;
    wcout << fmt::format(L"abs(PI - π): {0:.10e}", abs(PI - M_PI)) << endl;
    return 0;
}