gcd.cpp

#include <iostream>

using namespace std;

template <int x, int y>
struct gcd {
    enum { value = gcd<y, x%y>::value };
};

template <int x>
struct gcd<x, 0> {
    enum { value = x };
};

template <int n>
struct fibb {
    enum { value = fibb<n - 1>::value + fibb<n - 2>::value };
};

template <>
struct fibb<0> {
    enum { value = 1 };
};

template <>
struct fibb<1> {
    enum { value = 1 };
};

template <int x, int y, int... rest>
struct maxi {
    enum { value = x > y ? maxi<x, rest...>::value : maxi<y, rest...>::value };
};

template <int x, int y>
struct maxi<x, y> {
    enum { value = x > y ? x : y };
};

int main(int, char *[])
{
    cout << "GCD: 5,4: " << gcd<5,4>::value << endl;
    cout << "GCD: 10, 5: " << gcd<10, 5>::value << endl;
    cout << "GCD: 18, 8: " << gcd<18, 8>::value << endl;
    cout << "GCD: 894744, 2312: " << gcd<894744, 2312>::value << endl;
    cout << "GCD: 100, 10000: " << gcd<100, 10000>::value << endl;
    cout << "GCD: 40, 50: " << gcd<40,50>::value << endl;
    cout << "fibb 0: " << fibb<0>::value << endl;
    cout << "fibb 1: " << fibb<1>::value << endl;
    cout << "fibb 2: " << fibb<2>::value << endl;
    cout << "fibb 3: " << fibb<3>::value << endl;
    cout << "fibb 4: " << fibb<4>::value << endl;
    cout << "fibb 5: " << fibb<5>::value << endl;
    cout << "fibb 6: " << fibb<6>::value << endl;
    cout << "max 5, 6, 7, 8, 9: " << maxi<5, 6, 7,8,9>::value << endl;
}