I think you have to use the time as argument for the generator<br>�<font size="1"><span style="font-family: courier new,monospace;">mt19937 gen(time(0));</span></font><br><br><div class="gmail_quote">2011/1/24 Zolt�n Lengyel <span dir="ltr"><<a href="mailto:katzlengyel@gmail.com">katzlengyel@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hello,<br>I am trying to make a simple program that can generate random integers in range, using boost::uniform_int.<br>
<br><a href="http://www.boost.org/doc/libs/1_45_0/doc/html/boost_random/tutorial.html#boost_random.tutorial.generating_integers_in_a_range" target="_blank">http://www.boost.org/doc/libs/1_45_0/doc/html/boost_random/tutorial.html#boost_random.tutorial.generating_integers_in_a_range</a><br>
This tutorial tells:<br>"We use <code><a href="http://www.boost.org/doc/libs/1_45_0/doc/html/boost/mt19937.html" title="Type definition mt19937" target="_blank">mt19937</a></code> 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 (<code><span>std</span><span>::</span><span>time</span><span>(</span><span>0</span><span>)</span></code> defined in ctime)."<br>
<br>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.<br>
<br><br><font size="1"><span style="font-family: courier new,monospace;">#include "uniform_int.hpp"</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">#include "boost/random/variate_generator.hpp"</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">#include "boost/random/mersenne_twister.hpp"</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">#include <time.h></span><br style="font-family: courier new,monospace;">
<br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">#include <iostream></span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">using namespace std;</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">using namespace boost;</span><br style="font-family: courier new,monospace;"><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">mt19937 gen;</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">// time_t gen = time(0);</span><br style="font-family: courier new,monospace;"><br style="font-family: courier new,monospace;"><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">int roll_die()</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">{</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">��� uniform_int<> dist(1, 6);</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">��� variate_generator<mt19937&, uniform_int<> > die(gen, dist);</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">��� //boost::variate_generator<time_t, boost::uniform_int<> > die(gen, dist);</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">��� return die();</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">}</span><br style="font-family: courier new,monospace;"><br style="font-family: courier new,monospace;"><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">int main()</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">{</span><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">��� for (int i = 0; i < 5; i++)</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">��� ��� cout << roll_die() << endl;</span><br style="font-family: courier new,monospace;"><br style="font-family: courier new,monospace;"><span style="font-family: courier new,monospace;">��� return 0;</span><br style="font-family: courier new,monospace;">
<span style="font-family: courier new,monospace;">}</span></font><br><br>So, I would be glad, if someone could fix this for me, to have a different seed (depending on system time) at each start.<br>Thanks!
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