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26 <div class=
"titlepage"><div><div><h4 class=
"title">
27 <a name=
"boost_multiprecision.tut.rational.cpp_rational"></a><a class=
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"cpp_rational.html" title=
"cpp_rational">cpp_rational
</a>
28 </h4></div></div></div>
30 <code class=
"computeroutput"><span class=
"preprocessor">#include
</span> <span class=
"special"><</span><span class=
"identifier">boost
</span><span class=
"special">/
</span><span class=
"identifier">multiprecision
</span><span class=
"special">/
</span><span class=
"identifier">cpp_int
</span><span class=
"special">.
</span><span class=
"identifier">hpp
</span><span class=
"special">></span></code>
32 <pre class=
"programlisting"><span class=
"keyword">namespace
</span> <span class=
"identifier">boost
</span><span class=
"special">{
</span> <span class=
"keyword">namespace
</span> <span class=
"identifier">multiprecision
</span><span class=
"special">{
</span>
34 <span class=
"keyword">typedef
</span> <span class=
"identifier">rational_adaptor
</span><span class=
"special"><</span><span class=
"identifier">cpp_int_backend
</span><span class=
"special"><></span> <span class=
"special">></span> <span class=
"identifier">cpp_rational_backend
</span><span class=
"special">;
</span>
36 <span class=
"keyword">typedef
</span> <span class=
"identifier">number
</span><span class=
"special"><</span><span class=
"identifier">cpp_rational_backend
</span><span class=
"special">></span> <span class=
"identifier">cpp_rational
</span><span class=
"special">;
</span>
38 <span class=
"special">}}
</span> <span class=
"comment">// namespaces
</span>
41 The
<code class=
"computeroutput"><span class=
"identifier">cpp_rational_backend
</span></code>
42 type is used via the typedef
<code class=
"computeroutput"><span class=
"identifier">boost
</span><span class=
"special">::
</span><span class=
"identifier">multiprecision
</span><span class=
"special">::
</span><span class=
"identifier">cpp_rational
</span></code>.
43 It provides a rational number type that is a drop-in replacement for the
44 native C++ number types, but with unlimited precision.
47 As well as the usual conversions from arithmetic and string types, instances
48 of
<code class=
"computeroutput"><span class=
"identifier">cpp_rational
</span></code> are copy
49 constructible and assignable from type
<code class=
"computeroutput"><span class=
"identifier">cpp_int
</span></code>.
52 There is also a two argument constructor that accepts a numerator and denominator:
53 both of type
<code class=
"computeroutput"><span class=
"identifier">cpp_int
</span></code>.
56 There are also non-member functions:
58 <pre class=
"programlisting"><span class=
"identifier">cpp_int
</span> <span class=
"identifier">numerator
</span><span class=
"special">(
</span><span class=
"keyword">const
</span> <span class=
"identifier">cpp_rational
</span><span class=
"special">&);
</span>
59 <span class=
"identifier">cpp_int
</span> <span class=
"identifier">denominator
</span><span class=
"special">(
</span><span class=
"keyword">const
</span> <span class=
"identifier">cpp_rational
</span><span class=
"special">&);
</span>
62 which return the numerator and denominator of the number.
65 Things you should know when using this type:
67 <div class=
"itemizedlist"><ul class=
"itemizedlist" style=
"list-style-type: disc; ">
69 Default constructed
<code class=
"computeroutput"><span class=
"identifier">cpp_rational
</span></code>s
73 Division by zero results in a
<code class=
"computeroutput"><span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">overflow_error
</span></code>
77 Conversion from a string results in a
<code class=
"computeroutput"><span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">runtime_error
</span></code>
78 being thrown if the string can not be interpreted as a valid rational
83 <a name=
"boost_multiprecision.tut.rational.cpp_rational.h0"></a>
84 <span class=
"phrase"><a name=
"boost_multiprecision.tut.rational.cpp_rational.example"></a></span><a class=
"link" href=
"cpp_rational.html#boost_multiprecision.tut.rational.cpp_rational.example">Example:
</a>
86 <pre class=
"programlisting"><span class=
"preprocessor">#include
</span> <span class=
"special"><</span><span class=
"identifier">boost
</span><span class=
"special">/
</span><span class=
"identifier">multiprecision
</span><span class=
"special">/
</span><span class=
"identifier">cpp_int
</span><span class=
"special">.
</span><span class=
"identifier">hpp
</span><span class=
"special">></span>
87 <span class=
"preprocessor">#include
</span> <span class=
"special"><</span><span class=
"identifier">iostream
</span><span class=
"special">></span>
89 <span class=
"keyword">int
</span> <span class=
"identifier">main
</span><span class=
"special">()
</span>
90 <span class=
"special">{
</span>
91 <span class=
"keyword">using
</span> <span class=
"keyword">namespace
</span> <span class=
"identifier">boost
</span><span class=
"special">::
</span><span class=
"identifier">multiprecision
</span><span class=
"special">;
</span>
93 <span class=
"identifier">cpp_rational
</span> <span class=
"identifier">v
</span> <span class=
"special">=
</span> <span class=
"number">1</span><span class=
"special">;
</span>
95 <span class=
"comment">// Do some arithmetic:
</span>
96 <span class=
"keyword">for
</span><span class=
"special">(
</span><span class=
"keyword">unsigned
</span> <span class=
"identifier">i
</span> <span class=
"special">=
</span> <span class=
"number">1</span><span class=
"special">;
</span> <span class=
"identifier">i
</span> <span class=
"special"><=
</span> <span class=
"number">1000</span><span class=
"special">;
</span> <span class=
"special">++
</span><span class=
"identifier">i
</span><span class=
"special">)
</span>
97 <span class=
"identifier">v
</span> <span class=
"special">*=
</span> <span class=
"identifier">i
</span><span class=
"special">;
</span>
98 <span class=
"identifier">v
</span> <span class=
"special">/=
</span> <span class=
"number">10</span><span class=
"special">;
</span>
100 <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">cout
</span> <span class=
"special"><<</span> <span class=
"identifier">v
</span> <span class=
"special"><<</span> <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">endl
</span><span class=
"special">;
</span> <span class=
"comment">// prints
1000! /
10</span>
101 <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">cout
</span> <span class=
"special"><<</span> <span class=
"identifier">numerator
</span><span class=
"special">(
</span><span class=
"identifier">v
</span><span class=
"special">)
</span> <span class=
"special"><<</span> <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">endl
</span><span class=
"special">;
</span>
102 <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">cout
</span> <span class=
"special"><<</span> <span class=
"identifier">denominator
</span><span class=
"special">(
</span><span class=
"identifier">v
</span><span class=
"special">)
</span> <span class=
"special"><<</span> <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">endl
</span><span class=
"special">;
</span>
104 <span class=
"identifier">cpp_rational
</span> <span class=
"identifier">w
</span><span class=
"special">(
</span><span class=
"number">2</span><span class=
"special">,
</span> <span class=
"number">3</span><span class=
"special">);
</span> <span class=
"comment">// component wise constructor
</span>
105 <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">cout
</span> <span class=
"special"><<</span> <span class=
"identifier">w
</span> <span class=
"special"><<</span> <span class=
"identifier">std
</span><span class=
"special">::
</span><span class=
"identifier">endl
</span><span class=
"special">;
</span> <span class=
"comment">// prints
2/
3</span>
106 <span class=
"keyword">return
</span> <span class=
"number">0</span><span class=
"special">;
</span>
107 <span class=
"special">}
</span>
110 <table xmlns:
rev=
"http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width=
"100%"><tr>
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"left"></td>
112 <td align=
"right"><div class=
"copyright-footer">Copyright
© 2002-
2013 John Maddock and Christopher Kormanyos
<p>
113 Distributed under the Boost Software License, Version
1.0. (See accompanying
114 file LICENSE_1_0.txt or copy at
<a href=
"http://www.boost.org/LICENSE_1_0.txt" target=
"_top">http://www.boost.org/LICENSE_1_0.txt
</a>)
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