WSJT-X/boost/libs/math/example/nonfinite_facet_sstream.cpp

133 lines
3.5 KiB
C++

// nonfinite_facet_sstream.cpp
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)
// Copyright (c) 2006 Johan Rade
// Copyright (c) 2011 Paul A. Bristow
/*!
\file
\brief Examples of nonfinite with output and input facets and stringstreams.
\detail Contruct a new locale with the nonfinite_num_put and nonfinite_num_get
facets and imbue istringstream, ostringstream and stringstreams,
showing output and input (and loopback for the stringstream).
*/
#include <boost/math/special_functions/nonfinite_num_facets.hpp>
using boost::math::nonfinite_num_put;
using boost::math::nonfinite_num_get;
using boost::math::legacy;
#include <iostream>
using std::cout;
using std::endl;
#include <locale>
using std::locale;
#include <sstream>
using std::stringstream;
using std::istringstream;
using std::ostringstream;
#include <limits>
using std::numeric_limits;
#include <assert.h>
int main()
{
//[nonfinite_facets_sstream_1
locale old_locale;
locale tmp_locale(old_locale, new nonfinite_num_put<char>);
locale new_locale(tmp_locale, new nonfinite_num_get<char>);
//] [/nonfinite_facets_sstream_1]
// Note that to add two facets, nonfinite_num_put and nonfinite_num_get,
// you have to add one at a time, using a temporary locale.
{
ostringstream oss;
oss.imbue(new_locale);
double inf = numeric_limits<double>::infinity();
oss << inf; // Write out.
cout << "infinity output was " << oss.str() << endl;
assert(oss.str() == "inf");
}
{
istringstream iss;
iss.str("inf");
iss.imbue(new_locale);
double inf;
iss >> inf; // Read from "inf"
cout << "Infinity input was " << iss.str() << endl;
assert(inf == numeric_limits<double>::infinity());
}
{
//[nonfinite_facets_sstream_2
stringstream ss;
ss.imbue(new_locale);
double inf = numeric_limits<double>::infinity();
ss << inf; // Write out.
assert(ss.str() == "inf");
double r;
ss >> r; // Read back in.
assert(inf == r); // Confirms that the double values really are identical.
cout << "infinity output was " << ss.str() << endl;
cout << "infinity input was " << r << endl;
// But the string representation of r displayed will be the native type
// because, when it was constructed, cout had NOT been imbued
// with the new locale containing the nonfinite_numput facet.
// So the cout output will be "1.#INF on MS platforms
// and may be "inf" or other string representation on other platforms.
//] [/nonfinite_facets_sstream_2]
}
{
stringstream ss;
ss.imbue(new_locale);
double nan = numeric_limits<double>::quiet_NaN();
ss << nan; // Write out.
assert(ss.str() == "nan");
double v;
ss >> v; // Read back in.
cout << "NaN output was " << ss.str() << endl;
cout << "NaN input was " << v << endl;
// assert(nan == v); // Always fails because NaN == NaN fails!
// assert(nan == numeric_limits<double>::quiet_NaN()); asserts!
// And the string representation will be the native type
// because cout has NOT been imbued with a locale containing
// the nonfinite_numput facet.
// So the output will be "1.#QNAN on MS platforms
// and may be "nan" or other string representation on other platforms.
}
} // int main()
/*
//[nonfinite_facet_sstream_output
infinity output was inf
Infinity input was inf
infinity output was inf
infinity input was 1.#INF
NaN output was nan
NaN input was 1.#QNAN
//] [nonfinite_facet_sstream_output]
*/