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| 5 | <TITLE>Boost Numeric Conversion Library - Bounds</TITLE> |
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| 10 | <TR> |
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| 11 | <TH VALIGN="top" WIDTH="300"> |
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| 12 | <H3><A HREF="../../../../index.htm"><IMG HEIGHT="86" WIDTH="277" |
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| 13 | ALT="C++ Boost" SRC="../../../../boost.png" BORDER="0"></A></H3> </TH> |
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| 14 | <TH VALIGN="top"> |
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| 15 | <H1 ALIGN="center">Boost Numeric Conversion Library</H1> |
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| 16 | |
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| 17 | <H1><A HREF="http://www.boost.org">Header </A><A |
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| 18 | HREF="../../../../boost/numeric/conversion/bounds.hpp">boost/numeric/conversion/bounds.hpp</A></H1> |
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| 19 | </TH> |
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| 20 | </TR> |
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| 21 | </TABLE><HR> |
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| 22 | <H2>Contents</H2> |
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| 23 | <UL> |
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| 24 | <LI><A HREF="#introduction">Introduction</A></LI> |
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| 25 | <LI><A HREF="#bounds"><code>template class bounds<N></CODE></A></LI> |
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| 26 | <LI><A HREF="#examples">Examples</A></LI> |
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| 27 | <!--<LI><A HREF="#implementation">Implementation</A></LI>--> |
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| 28 | <!--<LI><A HREF="#portability">Portability</A></LI>--> |
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| 29 | </UL> <HR> |
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| 30 | <H2><A NAME="introduction">Introduction</A></H2> |
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| 31 | <P>To determine the ranges of numeric types with std:: numeric_limits |
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| 32 | [18.2.1], different syntax have to be used depending on numeric type. |
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| 33 | Specifically, numeric_limits<T>::min() for integral types returns the |
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| 34 | minimum finite value, whereas for floating point types it returns the minimum |
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| 35 | positive normalized value. The difference in semantics makes client code |
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| 36 | unnecessarily complex and error prone. <BR> <BR> |
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| 37 | boost::numeric::bounds<> provides a consistent interface for retrieving |
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| 38 | the maximum finite value, the minimum finite value and the minimum positive |
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| 39 | normalized value (0 for integral types) for numeric types. The selection of |
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| 40 | implementation is performed at compile time, so there is no runtime overhead. |
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| 41 | <BR> |
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| 42 | <BR> </P> <HR> |
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| 43 | <H2><A NAME="bounds"><CODE>traits class bounds<N></CODE></A></H2> |
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| 44 | <BLOCKQUOTE> |
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| 45 | |
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| 46 | <PRE>template<class N> |
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| 47 | struct bounds |
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| 48 | { |
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| 49 | static N lowest () { return <i>implementation_defined</i>; } |
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| 50 | static N highest () { return <i>implementation_defined</i>; } |
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| 51 | static N smallest() { return <i>implementation_defined</i>; } |
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| 52 | };</PRE> |
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| 53 | </BLOCKQUOTE> |
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| 54 | <H3>Members</H3> |
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| 55 | <PRE>lowest()</PRE> |
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| 56 | <P>Returns the minimum finite value, equivalent to |
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| 57 | numeric_limits<T>::min() when T is an integral type, and to |
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| 58 | -numeric_limits<T>::max() when T is a floating point type. </P> |
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| 59 | <PRE>highest()</PRE> |
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| 60 | <P>Returns the maximum finite value, equivalent to |
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| 61 | numeric_limits<T>::max(). </P> |
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| 62 | <PRE>smallest()</PRE> |
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| 63 | |
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| 64 | <P>Returns the smallest positive normalized value for floating point types with |
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| 65 | denormalization, or returns 0 for integral types. <BR> |
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| 66 | <BR> |
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| 67 | </P> <HR> |
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| 68 | <H2><A NAME="examples">Examples</A></H2> |
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| 69 | |
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| 70 | <P>The following example demonstrates the use of numeric::bounds<> and the |
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| 71 | equivalent code using numeric_limits: </P> |
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| 72 | |
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| 73 | <BLOCKQUOTE> |
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| 74 | <PRE>#include <iostream> |
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| 75 | |
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| 76 | #include <boost/numeric/conversion/bounds.hpp> |
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| 77 | #include <boost/limits.hpp> |
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| 78 | |
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| 79 | int main() { |
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| 80 | |
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| 81 | std::cout << "numeric::bounds versus numeric_limits example.\n"; |
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| 82 | |
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| 83 | std::cout << "The maximum value for float:\n"; |
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| 84 | std::cout << boost::numeric::bounds<float>::highest() << "\n"; |
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| 85 | std::cout << std::numeric_limits<float>::max() << "\n"; |
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| 86 | |
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| 87 | std::cout << "The minimum value for float:\n"; |
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| 88 | std::cout << boost::numeric::bounds<float>::lowest() << "\n"; |
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| 89 | std::cout << -std::numeric_limits<float>::max() << "\n"; |
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| 90 | |
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| 91 | std::cout << "The smallest positive value for float:\n"; |
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| 92 | std::cout << boost::numeric::bounds<float>::smallest() << "\n"; |
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| 93 | std::cout << std::numeric_limits<float>::min() << "\n"; |
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| 94 | |
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| 95 | return 0; |
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| 96 | }</PRE> |
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| 97 | </BLOCKQUOTE> |
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| 98 | |
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| 99 | <hr> |
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| 100 | <P>Back to <A HREF="index.html">Numeric Conversion library index</A></P> |
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| 101 | <HR> |
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| 102 | <P>Revised 23 June 2004</P> |
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| 103 | <p>© Copyright Fernando Luis Cacciola Carballal, 2004</p> |
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| 104 | <p> Use, modification, and distribution are subject to the Boost Software |
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| 105 | License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt"> |
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| 106 | LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt"> |
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| 107 | www.boost.org/LICENSE_1_0.txt</a>)</p> |
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