what is >> expected to do if the number input it "out of range"? can we, for example, write cin >> month; (see below for definition of month)? should this be using numeric_limits<T>::epsilon() (instead of DBL_EPSILON) and would that even work for numbers larger than 2.0? At Friday 2004-05-14 14:08, you wrote:
There has been some discussion previously on this list for a ranged type. My personal desire was to have new double types in the ranges [0.0, 1.0) and [0.0, 1.0] among other things. There are several other uses that I can imagine. Feel free to rip this apart or do whatever you want.
#include <float.h> #include <assert.h>
namespace boost { // a simple range class template<class policy> class range { public: typedef range<policy> self; typedef typename policy::value value; range() : m(min()) { } range(const self& x) : m(x) { } range(const value& x) { m = rangeAssert(x); } static const value min() { return policy::min(); } static const value max() { return policy::max(); } operator value() { return m; } self& operator=(const self& x) { m = x; return *this; } self& operator=(const value& x) { m = rangeAssert(x); return *this; } const value& rangeAssert(const value& x) const { assert(x <= max()); assert(x >= min()); return x; }; private: value m; };
// some range policies struct RangePolicyZeroToOne { typedef double value; static const value min() { return 0.0; }; static const value max() { return 1.0; }; };
struct RangePolicyZeroToBelowOne { typedef double value; static const value min() { return 0.0; }; static const value max() { return 1.0 - DBL_EPSILON; }; };
struct RangePolicyPercent { typedef double value; static const value min() { return 0.0; }; static const value max() { return 100.0; }; };
struct RangePolicyDegrees { typedef double value; static const value min() { return 0.0; }; static const value max() { return 360.0 - DBL_EPSILON; }; };
struct RangePolicyRadians { typedef double value; static const value min() { return 0.0; }; static const value max() { return (2 * PI) - DBL_EPSILON; }; };
template <typename T, T min_T, T max_T> struct StaticRange { typedef T value; static const value min() { return min_T; }; static const value max() { return max_T; }; }
// some sample types made with ranges typedef range<RangePolicyZeroToOne> Probability; typedef range<RangePolicyZeroToBelowOne> Distribution; typedef range<RangePolicyPercent> Percent; typedef range<RangePolicyDegrees> Degrees; typedef range<RangePolicyRadians> Radians; typedef range<RangePolicyStatic<int, 0, 11> > Month; typedef range<RangePolicyStatic<int, 0, 364> > DayOfTheYear; typedef range<RangePolicyStatic<int, 0, 6> > DayOfTheWeek; typedef range<RangePolicyStatic<char, 'a', 'z'> > LowerCaseLetter; typedef range<RangePolicyStatic<char, 'A', 'Z'> > UpperCaseLetter; typedef range<RangePolicyStatic<char, '0', '9'> > NumberChar; };
by Christopher Diggins licensed under the Boost software license
http://www.cdiggins.com http://www.heron-language.com
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