C use function's output as functions input n times-CodePudding

I'm sorry for the weird title. I don't know how to word this. If I have function func() How do I do this:

func(func(func(func(func(x)))))

where it repeats N times?

I'm trying to implement Conway's Game of Life. I have a function that takes a vector and outputs another vector, which is the next generation of the input vector. So generation 3's vector would be func(func(func(x))).

CodePudding user response：

The easy way, simply using for loop:

int x = some_initial_value;
for (int i = 0; i < NUMBER_OF_ITERATIONS;   i)
{
    x = func(x);
}

CodePudding user response：

While the 'easy way' works in most cases, I'd like to provide you a way to do in in cases where return type (for a given argument type) might differ from argument type:

template<size_t i, typename F, typename Arg>
auto times(F f, const Arg& arg) {
    if constexpr (i == 0) {
        return arg;
    } else {
        return times<i - 1>(f, f(arg));
    }
}

// usage: times<5>(func, x);