/******************************************************************************
 * Various trigonometric approximations to Pi.
 * 
 * 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;

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

    double const pi1 = atan(1.0) * 4.0;
    double const pi2 = atan2(0.0, -1.0);
    double const pi3 = acos(-1.0);
    double const pi4 = 2.0 * acos(0.0);

    wcout << fmt::format(L"pi1: {0:.15f}", pi1) << endl;
    wcout << fmt::format(L"abs(pi1 - π): {0:.10e}", abs(pi1 - M_PI)) << endl;
    wcout << fmt::format(L"pi2: {0:.15f}", pi2) << endl;
    wcout << fmt::format(L"abs(pi2 - π): {0:.10e}", abs(pi2 - M_PI)) << endl;
    wcout << fmt::format(L"pi3: {0:.15f}", pi3) << endl;
    wcout << fmt::format(L"abs(pi3 - π): {0:.10e}", abs(pi3 - M_PI)) << endl;
    wcout << fmt::format(L"pi4: {0:.15f}", pi4) << endl;
    wcout << fmt::format(L"abs(pi4 - π): {0:.10e}", abs(pi4 - M_PI)) << endl;
    return 0;
}