Re: [boost] [random] example code fails inside struct

Subject: Re: [boost] [random] example code fails inside struct
From: Gevorg Voskanyan (v_gevorg_at_[hidden])
Date: 2011-04-16 08:32:13

Beman Dawes wrote:
> > You can't initialize a class data  member like that.
> > boost::uniform_int<> million(1,1000000);  is  valid in a function body or in
> > namespace-scope, but not in class  scope...
> 
> Doesn't that create a usage problem because there aren't  alternative
> constructors that do work at class  scope?

What do you mean? If I guess what you're asking here correctly, then that is a 
limitation in C++03 addressed in C++11. Here's the proposal for 
that: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2756.htm
It still won't make the code to compile as you have written it, but with slight 
changes it will:

struct X
  {
    boost::mt19937 rng;
    boost::uniform_int<> million{1,1000000};  // or million 
= boost::uniform_int<>(1, 1000000);
    boost::variate_generator<boost::mt19937&, boost::uniform_int<> >
            random_value{rng, million};
  };

Please let me know if that info wasn't what you were looking for.

HTH,
Gevorg