Add a random choice from container function

This commit is contained in:
Danny Robson 2012-01-04 17:03:27 +11:00
parent e2b56f3b77
commit f07dda9116

View File

@ -20,12 +20,33 @@
#ifndef __UTIL_RANDOM_HPP #ifndef __UTIL_RANDOM_HPP
#define __UTIL_RANDOM_HPP #define __UTIL_RANDOM_HPP
#include <iterator>
namespace util { namespace util {
template <typename T> template <typename T>
T& randomise (T &); T& randomise (T &);
template <typename T> template <typename T>
T random (void); T random (void);
template <typename T>
typename T::value_type&
choose (T &container) {
typename T::iterator cursor = container.begin ();
typename T::size_type size = container.size ();
typename T::size_type offset = random<typename T::size_type> () % size;
std::advance (cursor, offset);
return *cursor;
}
template <typename T>
typename T::value_type&
choose (T begin, T end) {
typename T::difference_type size = std::distance (begin, end);
std::advance (begin, random<T::size_type> () % size);
return *begin;
}
} }
#endif #endif