Re: [Boost-users] having a problem seeding random number generator.

Jim Ingram wrote:

Some more information:

I'm using gcc 4.0.2 on Ubuntu, with the latest available version of Boost (for Ubuntu anyway. It's 1.32.0+1.33.0-cvs20050727). That's the version from Ubuntu Breezy, 1.33.1 is in Dapper.

I'm writing a class that is supposed to simulate a six-sided die. It compiles and everything works, except seeding the mt19937. Every time I try testing this class, I get the same numbers, no matter what value I call my seed method with. The problem is that 'variate_generator' stores a copy of the engine, not a reference. So this works:

#include class D6 { typedef boost::mt19937 engine_t; typedef boost::uniform_int<> dist_t; typedef boost::variate_generator gen_t; public: D6() : die(engine_t(), dist_t(1,6)) { } explicit D6(boost::uint32_t s) : die(engine_t(s), dist_t(1,6)) { } int roll() { return die(); } void seed(boost::uint32_t s) { die.engine().seed(s); } private: gen_t die; };