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- // die.cpp
- //
- // Copyright (c) 2009
- // Steven Watanabe
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- //[die
- /*`
- For the source of this example see
- [@boost://libs/random/example/die.cpp die.cpp].
- First we include the headers we need for __mt19937
- and __uniform_int_distribution.
- */
- #include <boost/random/mersenne_twister.hpp>
- #include <boost/random/uniform_int_distribution.hpp>
- /*`
- 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).
- */
- boost::random::mt19937 gen;
- /*`
- [note We are using a /global/ generator object here. This
- is important because we don't want to create a new [prng
- pseudo-random number generator] at every call]
- */
- /*`
- Now we can define a function that simulates an ordinary
- six-sided die.
- */
- int roll_die() {
- /*<< __mt19937 produces integers in the range [0, 2[sup 32]-1].
- However, we want numbers in the range [1, 6]. The distribution
- __uniform_int_distribution performs this transformation.
- [warning Contrary to common C++ usage __uniform_int_distribution
- does not take a /half-open range/. Instead it takes a /closed range/.
- Given the parameters 1 and 6, __uniform_int_distribution
- can produce any of the values 1, 2, 3, 4, 5, or 6.]
- >>*/
- boost::random::uniform_int_distribution<> dist(1, 6);
- /*<< A distribution is a function object. We generate a random
- number by calling `dist` with the generator.
- >>*/
- return dist(gen);
- }
- //]
- #include <iostream>
- int main() {
- for(int i = 0; i < 10; ++i) {
- std::cout << roll_die() << std::endl;
- }
- }
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