Re: Reading and Writing float value of infinity to file.

"Victor Bazarov" <>
Fri, 19 Oct 2007 09:00:45 -0400
Jim Langston wrote:

Well, this is what I think I'll put into production, unless anyone
can show me any flaws in it. It seems to work fine as a float in my
rudimentary tests.

namespace jml
   class Float
       Float( float Value = 0.0f ): Value( Value ) {}
       operator float() { return Value; }
       float Value;

   std::istream& operator>>( std::istream& is, Float& mf )
       if ( is >> mf.Value )
           if ( mf.Value == 1.0f && is.peek() == '#' )
               std::string Rest;
               is >> Rest;
               if ( Rest == "#INF" )
                   mf.Value = std::numeric_limits<float>::infinity();

       return is;


I'll probably make Value private just because.

Actually, I'd probably get rid of 'operator float()' in it (besides,
it ought to be declared 'const' if you ask me), and always use the
explicit ".Value", or have a function called "value()" in it instead:

    class Float
        float value() const { return Value; }
        float Value;

Recently in our development we ran into some implicit conversions
that we didn't want, and it was all due to type conversion functions
(which BTW you can't declare "explicit"). We decided we didn't like
those in our own types.

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