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 Hu Chunming
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// Boost.Units - A C++ library for zero-overhead dimensional analysis and
// unit/quantity manipulation and conversion
//
// Copyright (C) 2003-2008 Matthias Christian Schabel
// Copyright (C) 2008 Steven Watanabe
//
// 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)
/**
\file
\brief Example of using autoprefixes.
\details
Example of using engineering (10^3) and binary (2^10) autoprefixes.
Output:
@verbatim
autoprefixes.cpp
using native typeof
Linking...
Embedding manifest...
Autorun "j:\Cpp\Misc\debug\autoprefixes.exe"
2.345 m
2.345 km
5.49902 MJ
5.49902 megajoule
2.048 kb
2 Kib
2345.6
23456
2345.6
23456
m
meter
0
1
@endverbatim
//[autoprefixes_output
//] [/autoprefixes_output
**/
#include <iostream>
#include <boost/units/io.hpp>
#include <boost/units/pow.hpp>
#include <boost/units/systems/si.hpp>
#include <boost/units/systems/si/io.hpp>
#include <boost/units/quantity.hpp>
struct byte_base_unit : boost::units::base_unit<byte_base_unit, boost::units::dimensionless_type, 3>
{
static constexpr const char* name() { return("byte"); }
static constexpr const char* symbol() { return("b"); }
};
struct thing_base_unit : boost::units::base_unit<thing_base_unit, boost::units::dimensionless_type, 4>
{
static constexpr const char* name() { return("thing"); }
static constexpr const char* symbol() { return(""); }
};
struct euro_base_unit : boost::units::base_unit<euro_base_unit, boost::units::dimensionless_type, 5>
{
static constexpr const char* name() { return("EUR"); }
static constexpr const char* symbol() { return("€"); }
};
int main()
{
using std::cout;
using std::endl;
using namespace boost::units;
using namespace boost::units::si;
//[autoprefixes_snippet_1
using boost::units::binary_prefix;
using boost::units::engineering_prefix;
using boost::units::no_prefix;
quantity<length> l = 2.345 * meters; // A quantity of length, in units of meters.
cout << engineering_prefix << l << endl; // Outputs "2.345 m".
l = 1000.0 * l; // Increase it by 1000, so expect a k prefix.
// Note that a double 1000.0 is required - an integer will fail to compile.
cout << engineering_prefix << l << endl; // Output autoprefixed with k to "2.345 km".
quantity<energy> e = kilograms * pow<2>(l / seconds); // A quantity of energy.
cout << engineering_prefix << e << endl; // 5.49902 MJ
cout << name_format << engineering_prefix << e << endl; // 5.49902 megaJoule
//] [/autoprefixes_snippet_1]
//[autoprefixes_snippet_2
// Don't forget that the units name or symbol format specification is persistent.
cout << symbol_format << endl; // Resets the format to the default symbol format.
quantity<byte_base_unit::unit_type> b = 2048. * byte_base_unit::unit_type();
cout << engineering_prefix << b << endl; // 2.048 kb
cout << symbol_format << binary_prefix << b << endl; // "2 Kib"
//] [/autoprefixes_snippet_2]
// Note that scalar dimensionless values are *not* prefixed automatically by the engineering_prefix or binary_prefix iostream manipulators.
//[autoprefixes_snippet_3
const double s1 = 2345.6;
const long x1 = 23456;
cout << engineering_prefix << s1 << endl; // 2345.6
cout << engineering_prefix << x1 << endl; // 23456
cout << binary_prefix << s1 << endl; // 2345.6
cout << binary_prefix << x1 << endl; // 23456
//] [/autoprefixes_snippet_3]
//[autoprefixes_snippet_4
const length L; // A unit of length (but not a quantity of length).
cout << L << endl; // Default length unit is meter,
// but default is symbol format so output is just "m".
cout << name_format << L << endl; // default length name is "meter".
//] [/autoprefixes_snippet_4]
//[autoprefixes_snippet_5
no_prefix(cout); // Clear any prefix flag.
cout << no_prefix << endl; // Clear any prefix flag using `no_prefix` manipulator.
//] [/autoprefixes_snippet_5]
//[autoprefixes_snippet_6
cout << boost::units::get_autoprefix(cout) << endl; // 8 is `autoprefix_binary` from `enum autoprefix_mode`.
cout << boost::units::get_format(cout) << endl; // 1 is `name_fmt` from `enum format_mode`.
//] [/autoprefixes_snippet_6]
quantity<thing_base_unit::unit_type> t = 2048. * thing_base_unit::unit_type();
cout << name_format << engineering_prefix << t << endl; // 2.048 kilothing
cout << symbol_format << engineering_prefix << t << endl; // 2.048 k
cout << binary_prefix << t << endl; // "2 Ki"
quantity<euro_base_unit::unit_type> ce = 2048. * euro_base_unit::unit_type();
cout << name_format << engineering_prefix << ce << endl; // 2.048 kiloEUR
cout << symbol_format << engineering_prefix << ce << endl; // 2.048 k€
return 0;
} // int main()
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