integer_pow.hpp

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/// @file integer_pow.hpp
/// @brief Compile-time integer exponentiation via repeated squaring
#pragma once
 
namespace num {
 
/// @brief Compute x^N at compile time via repeated squaring.
template<int N, typename T>
constexpr T ipow(T x) noexcept {
    static_assert(N >= 0, "ipow: exponent must be non-negative");
    if constexpr (N == 0)
        return T(1);
    if constexpr (N == 1)
        return x;
    if constexpr (N % 2 == 0) {
        const T half = ipow<N / 2>(x);
        return half * half;
    } else {
        return x * ipow<N - 1>(x);
    }
}
 
} // namespace num