Template with functor parameter.

template_functor_parameter.cpp

struct linear
{
	int operator()(const int value) const
	{
		return value;
	}
};

struct logarithmic
{
	int operator()(const int value) const
	{
		return (value * value) >> 8;
	}
};

template<typename T = linear>
struct calculator
{
	T m_func;

	int call(const int value)
	{
		return m_func(value);
	}
};

int main(int, char **)
{
	calculator<linear> flin;
	std::cout << flin.call(100) << std::endl;

	calculator<logarithmic> flog;
	std::cout << flog.call(100) << std::endl;

	return 0;
}