#include "uniform_int.hpp"
#include "boost/random/variate_generator.hpp"
#include "boost/random/mersenne_twister.hpp"
#include <time.h>

#include <iostream>
using namespace std;
using namespace boost;

time_t T = time(0);
mt19937 gen(T);

int roll_die()
{
    uniform_int<> dist(1, 6);
    variate_generator<mt19937&, uniform_int<> > die(gen, dist);
    return die();
}


int main()
{
    for (int i = 0; i < 5; i++)
        cout << roll_die() << endl;

    return 0;
}



Thanks for your help, it works this way.


On 24 January 2011 15:33, Hernán Leoni <leoni.hernan@gmail.com> wrote:
I think you have to use the time as argument for the generator
 mt19937 gen(time(0));

2011/1/24 Zoltán Lengyel <katzlengyel@gmail.com>
Hello,
I am trying to make a simple program that can generate random integers in range, using boost::uniform_int.

http://www.boost.org/doc/libs/1_45_0/doc/html/boost_random/tutorial.html#boost_random.tutorial.generating_integers_in_a_range
This tutorial tells:
"We use mt19937 with the default seed as a source of randomness. The numbers produced will be the same every time the program is run. One common method to change this is to seed with the current time (std::time(0) defined in ctime)."

I have trouble getting this common method compile and work. Here's a tiny program that works, with the same seed at every run (like what the tutorial does), I have commented out my desperate tries to make the seed change.


#include "uniform_int.hpp"
#include "boost/random/variate_generator.hpp"
#include "boost/random/mersenne_twister.hpp"
#include <time.h>

#include <iostream>
using namespace std;
using namespace boost;

mt19937 gen;
// time_t gen = time(0);


int roll_die()
{
    uniform_int<> dist(1, 6);
    variate_generator<mt19937&, uniform_int<> > die(gen, dist);
    //boost::variate_generator<time_t, boost::uniform_int<> > die(gen, dist);
    return die();
}


int main()
{
    for (int i = 0; i < 5; i++)
        cout << roll_die() << endl;

    return 0;
}


So, I would be glad, if someone could fix this for me, to have a different seed (depending on system time) at each start.
Thanks!
_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
http://lists.boost.org/mailman/listinfo.cgi/boost-users


_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
http://lists.boost.org/mailman/listinfo.cgi/boost-users