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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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)
#ifndef NODE_DWA2004110_HPP
# define NODE_DWA2004110_HPP
# include <iostream>
// Polymorphic list node base class
struct node_base
{
node_base() : m_next(0) {}
virtual ~node_base()
{
delete m_next;
}
node_base* next() const
{
return m_next;
}
virtual void print(std::ostream& s) const = 0;
virtual void double_me() = 0;
void append(node_base* p)
{
if (m_next)
m_next->append(p);
else
m_next = p;
}
private:
node_base* m_next;
};
inline std::ostream& operator<<(std::ostream& s, node_base const& n)
{
n.print(s);
return s;
}
template <class T>
struct node : node_base
{
node(T x)
: m_value(x)
{}
void print(std::ostream& s) const { s << this->m_value; }
void double_me() { m_value += m_value; }
private:
T m_value;
};
#endif // NODE_DWA2004110_HPP
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