]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | <html> |
2 | <head> | |
3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
4 | <title>gmp_int</title> | |
5 | <link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> | |
6 | <meta name="generator" content="DocBook XSL Stylesheets V1.77.1"> | |
7 | <link rel="home" href="../../../index.html" title="Chapter 1. Boost.Multiprecision"> | |
8 | <link rel="up" href="../ints.html" title="Integer Types"> | |
9 | <link rel="prev" href="cpp_int.html" title="cpp_int"> | |
10 | <link rel="next" href="tom_int.html" title="tom_int"> | |
11 | </head> | |
12 | <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> | |
13 | <table cellpadding="2" width="100%"><tr> | |
14 | <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> | |
15 | <td align="center"><a href="../../../../../../../index.html">Home</a></td> | |
16 | <td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> | |
17 | <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> | |
18 | <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> | |
19 | <td align="center"><a href="../../../../../../../more/index.htm">More</a></td> | |
20 | </tr></table> | |
21 | <hr> | |
22 | <div class="spirit-nav"> | |
23 | <a accesskey="p" href="cpp_int.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ints.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="tom_int.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> | |
24 | </div> | |
25 | <div class="section"> | |
26 | <div class="titlepage"><div><div><h4 class="title"> | |
27 | <a name="boost_multiprecision.tut.ints.gmp_int"></a><a class="link" href="gmp_int.html" title="gmp_int">gmp_int</a> | |
28 | </h4></div></div></div> | |
29 | <p> | |
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">gmp</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> | |
31 | </p> | |
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> | |
33 | ||
34 | <span class="keyword">class</span> <span class="identifier">gmp_int</span><span class="special">;</span> | |
35 | ||
36 | <span class="keyword">typedef</span> <span class="identifier">number</span><span class="special"><</span><span class="identifier">gmp_int</span> <span class="special">></span> <span class="identifier">mpz_int</span><span class="special">;</span> | |
37 | ||
38 | <span class="special">}}</span> <span class="comment">// namespaces</span> | |
39 | </pre> | |
40 | <p> | |
41 | The <code class="computeroutput"><span class="identifier">gmp_int</span></code> back-end is | |
42 | 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">mpz_int</span></code>. | |
43 | It acts as a thin wrapper around the <a href="http://gmplib.org" target="_top">GMP</a> | |
44 | <code class="computeroutput"><span class="identifier">mpz_t</span></code> to provide an integer | |
45 | type that is a drop-in replacement for the native C++ integer types, but | |
46 | with unlimited precision. | |
47 | </p> | |
48 | <p> | |
49 | As well as the usual conversions from arithmetic and string types, type | |
50 | <code class="computeroutput"><span class="identifier">mpz_int</span></code> is copy constructible | |
51 | and assignable from: | |
52 | </p> | |
53 | <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> | |
54 | <li class="listitem"> | |
55 | The <a href="http://gmplib.org" target="_top">GMP</a> native types: <code class="computeroutput"><span class="identifier">mpf_t</span></code>, <code class="computeroutput"><span class="identifier">mpz_t</span></code>, | |
56 | <code class="computeroutput"><span class="identifier">mpq_t</span></code>. | |
57 | </li> | |
58 | <li class="listitem"> | |
59 | Instances of <code class="computeroutput"><span class="identifier">number</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span></code> that are wrappers around those | |
60 | types: <code class="computeroutput"><span class="identifier">number</span><span class="special"><</span><span class="identifier">gmp_float</span><span class="special"><</span><span class="identifier">N</span><span class="special">></span> <span class="special">></span></code>, <code class="computeroutput"><span class="identifier">number</span><span class="special"><</span><span class="identifier">gmp_rational</span><span class="special">></span></code>. | |
61 | </li> | |
62 | </ul></div> | |
63 | <p> | |
64 | It's also possible to access the underlying <code class="computeroutput"><span class="identifier">mpz_t</span></code> | |
65 | via the <code class="computeroutput"><span class="identifier">data</span><span class="special">()</span></code> | |
66 | member function of <code class="computeroutput"><span class="identifier">gmp_int</span></code>. | |
67 | </p> | |
68 | <p> | |
69 | Things you should know when using this type: | |
70 | </p> | |
71 | <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> | |
72 | <li class="listitem"> | |
73 | No changes are made to the GMP library's global settings - so you can | |
74 | safely mix this type with existing code that uses <a href="http://gmplib.org" target="_top">GMP</a>. | |
75 | </li> | |
76 | <li class="listitem"> | |
77 | Default constructed <code class="computeroutput"><span class="identifier">gmp_int</span></code>s | |
78 | have the value zero (this is GMP's default behavior). | |
79 | </li> | |
80 | <li class="listitem"> | |
81 | Formatted IO for this type does not support octal or hexadecimal notation | |
82 | for negative values, as a result performing formatted output on this | |
83 | type when the argument is negative and either of the flags <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ios_base</span><span class="special">::</span><span class="identifier">oct</span></code> or <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ios_base</span><span class="special">::</span><span class="identifier">hex</span></code> | |
84 | are set, will result in a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span></code> | |
85 | will be thrown. | |
86 | </li> | |
87 | <li class="listitem"> | |
88 | 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> | |
89 | being thrown if the string can not be interpreted as a valid integer. | |
90 | </li> | |
91 | <li class="listitem"> | |
92 | 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> | |
93 | being thrown. | |
94 | </li> | |
95 | <li class="listitem"> | |
96 | Although this type is a wrapper around <a href="http://gmplib.org" target="_top">GMP</a> | |
97 | it will work equally well with <a href="http://mpir.org/" target="_top">MPIR</a>. | |
98 | Indeed use of <a href="http://mpir.org/" target="_top">MPIR</a> is recommended | |
99 | on Win32. | |
100 | </li> | |
101 | <li class="listitem"> | |
102 | This backend supports rvalue-references and is move-aware, making instantiations | |
103 | of <code class="computeroutput"><span class="identifier">number</span></code> on this backend | |
104 | move aware. | |
105 | </li> | |
106 | </ul></div> | |
107 | <h6> | |
108 | <a name="boost_multiprecision.tut.ints.gmp_int.h0"></a> | |
109 | <span class="phrase"><a name="boost_multiprecision.tut.ints.gmp_int.example"></a></span><a class="link" href="gmp_int.html#boost_multiprecision.tut.ints.gmp_int.example">Example:</a> | |
110 | </h6> | |
111 | <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">gmp</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> | |
112 | <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> | |
113 | ||
114 | <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> | |
115 | <span class="special">{</span> | |
116 | <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> | |
117 | ||
118 | <span class="identifier">mpz_int</span> <span class="identifier">v</span> <span class="special">=</span> <span class="number">1</span><span class="special">;</span> | |
119 | ||
120 | <span class="comment">// Do some arithmetic:</span> | |
121 | <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> | |
122 | <span class="identifier">v</span> <span class="special">*=</span> <span class="identifier">i</span><span class="special">;</span> | |
123 | ||
124 | <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!</span> | |
125 | ||
126 | <span class="comment">// Access the underlying representation:</span> | |
127 | <span class="identifier">mpz_t</span> <span class="identifier">z</span><span class="special">;</span> | |
128 | <span class="identifier">mpz_init</span><span class="special">(</span><span class="identifier">z</span><span class="special">);</span> | |
129 | <span class="identifier">mpz_set</span><span class="special">(</span><span class="identifier">z</span><span class="special">,</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">backend</span><span class="special">().</span><span class="identifier">data</span><span class="special">());</span> | |
130 | <span class="identifier">mpz_clear</span><span class="special">(</span><span class="identifier">z</span><span class="special">);</span> | |
131 | <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> | |
132 | <span class="special">}</span> | |
133 | </pre> | |
134 | </div> | |
135 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
136 | <td align="left"></td> | |
137 | <td align="right"><div class="copyright-footer">Copyright © 2002-2013 John Maddock and Christopher Kormanyos<p> | |
138 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
139 | 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>) | |
140 | </p> | |
141 | </div></td> | |
142 | </tr></table> | |
143 | <hr> | |
144 | <div class="spirit-nav"> | |
145 | <a accesskey="p" href="cpp_int.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ints.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="tom_int.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> | |
146 | </div> | |
147 | </body> | |
148 | </html> |