/r/dailyprogrammer Challenge 119 - Rup-Inc's solution

#include <iostream>

template <bool Condition, typename TrueResult, typename FalseResult>
class if_;

template <typename TrueResult, typename FalseResult>
struct if_<true, TrueResult, FalseResult>
{
    typedef TrueResult result;
};

template <typename TrueResult, typename FalseResult>
struct if_<false, TrueResult, FalseResult>
{
    typedef FalseResult result;
};


template <int dolars, int cents, int cent25 = 0, int cent10 = 0, int cent5 = 0, int cent1 = 0>
struct coinConverter{
    enum {
        Cent25 = coinConverter<dolars -1, cents, cent25 + 4, cent10, cent5, cent1>::Cent25,
        Cent10 = coinConverter<dolars -1, cents, cent25 + 4, cent10, cent5, cent1>::Cent10,
        Cent5 = coinConverter<dolars -1, cents, cent25 + 4, cent10, cent5, cent1>::Cent5,
        Cent1 = coinConverter<dolars -1, cents, cent25 + 4, cent10, cent5, cent1>::Cent1,
    };
};

template <int cents, int cent25, int cent10, int cent5, int cent1>
struct coinConverter<0, cents, cent25, cent10, cent5, cent1> {
    enum {
        Cent25 = if_<(cents >= 25), coinConverter<0, cents - 25, cent25 + 1, cent10, cent5, cent1>,
            if_<(cents >= 10), coinConverter<0, cents - 10, cent25, cent10 + 1, cent5, cent1>,
                if_<(cents >= 5), coinConverter<0, cents - 5, cent25, cent10, cent5 + 1, cent1>,
                    coinConverter<0, cents - 1, cent25, cent10, cent5, cent1 + 1>>::result>::result>::result::Cent25,
        Cent10 = if_<(cents >= 25), coinConverter<0, cents - 25, cent25 + 1, cent10, cent5, cent1>,
            if_<(cents >= 10), coinConverter<0, cents - 10, cent25, cent10 + 1, cent5, cent1>,
                if_<(cents >= 5), coinConverter<0, cents - 5, cent25, cent10, cent5 + 1, cent1>,
                    coinConverter<0, cents - 1, cent25, cent10, cent5, cent1 + 1>>::result>::result>::result::Cent10,
        Cent5 = if_<(cents >= 25), coinConverter<0, cents - 25, cent25 + 1, cent10, cent5, cent1>,
            if_<(cents >= 10), coinConverter<0, cents - 10, cent25, cent10 + 1, cent5, cent1>,
                if_<(cents >= 5), coinConverter<0, cents - 5, cent25, cent10, cent5 + 1, cent1>,
                    coinConverter<0, cents - 1, cent25, cent10, cent5, cent1 + 1>>::result>::result>::result::Cent5,
        Cent1 = if_<(cents >= 25), coinConverter<0, cents - 25, cent25 + 1, cent10, cent5, cent1>,
            if_<(cents >= 10), coinConverter<0, cents - 10, cent25, cent10 + 1, cent5, cent1>,
                if_<(cents >= 5), coinConverter<0, cents - 5, cent25, cent10, cent5 + 1, cent1>,
                    coinConverter<0, cents - 1, cent25, cent10, cent5, cent1 + 1>>::result>::result>::result::Cent1,
    };
};

template <int cent25, int cent10, int cent5, int cent1>
struct coinConverter<0, 0, cent25, cent10, cent5, cent1> {
    enum {
        Cent25 = cent25,
        Cent10 = cent10,
        Cent5 = cent5,
        Cent1 = cent1,
    };
};

#define CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(n) \
    template <int cent25, int cent10, int cent5, int cent1> \
    struct coinConverter<0, ## n ##, cent25, cent10, cent5, cent1> {\
    enum { Dolars = 0, Cents = 0, Cent25 = 0, Cent10 = 0, Cent5 = 0, Cent1 = 0 }; };

CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-1)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-2)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-3)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-4)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-5)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-6)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-7)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-8)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-9)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-10)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-11)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-12)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-13)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-14)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-15)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-16)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-17)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-18)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-19)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-20)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-21)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-22)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-23)
CREATE_CATCHING_COIN_CONVERTER_TEMPLATE(-24)

int main() {
    typedef coinConverter<0, 6> result;
    if (result::Cent25) std::cout << "$0.25 : " << result::Cent25 << std::endl;
    if (result::Cent10) std::cout << "$0.10 : " << result::Cent10 << std::endl;
    if (result::Cent5)  std::cout << "$0.05 : " << result::Cent5 << std::endl;
    if (result::Cent1)  std::cout << "$0.01 : " << result::Cent1 << std::endl;
}