ex-03.cpp (cpp-lecture/nim2/ex-03.cpp)

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#include <iostream>

template <unsigned int v>
struct Fac
{
    static constexpr unsigned int value = v*Fac<v-1>::value;
};

template <>
struct Fac<0>
{
    static constexpr unsigned int value = 1;
};

template <unsigned int v>
struct Fibo
{
    static constexpr unsigned int value = Fibo<v-1>::value + Fibo<v-2>::value;
};

template <>
struct Fibo<1>
{
    static constexpr unsigned int value = 1;
};

template <>
struct Fibo<0>
{
    static constexpr unsigned int value = 1;
};

template <unsigned int v>
struct Foo
{
    static constexpr unsigned int value = (v%2==0) ? Fac<v>::value
                                                   : Fibo<v>::value;
};

int
main()
{
    std::cout << Fibo<4>::value << std::endl;
    std::cout << Fibo<5>::value << std::endl;
    std::cout << Fac<4>::value << std::endl;
    std::cout << Fac<5>::value << std::endl;
    std::cout << Foo<4>::value << std::endl;
    std::cout << Fac<5>::value << std::endl;
}