Is it possible to create and initialize an array of values using template metaprogramming?

Question

I want to be able to create an array of calculated values (let\'s say for simplicity\'s sake that I want each value to be the square of it\'s index) at compile time using t

Answer 1

I'm not sure whether you want to see it done or find a library that will just do it for you. I assume the former.

template
struct SqArr {
    static inline void fill(int arr[]) {
        arr[N-1] = (N-1)*(N-1);
        SqArr::fill(arr);
    }
};

template<>
struct SqArr<0> {
    static inline void fill(int arr[]) { }
};

Now let's try to use this beast:

#include 
#include 
#include 

using namespace std;

int main(int argc, char* argv[])
{
    int arr[10];
    SqArr<10>::fill(arr);
    cout << endl;
    copy(arr, arr+10, ostream_iterator(cout, "\t"));
    cout << endl;
    return 0;
}

Note (confession): This isn't compile-time computation. To motivate that you can try to change the fourth line from SqArr::fill(arr); to SqArr::fill(arr); so the recursion is infinite, and you will see this compiles fine (when the compiler should in fact recurse indefinitely, or complain about the infinite recursion).