times.h

#pragma once

#include <cstddef>
#include <type_traits>

namespace basics {

class Times {
	size_t m_times;

public:
	constexpr explicit Times(size_t n) : m_times(n) {
	}

	template <typename Op>
	constexpr void operator()(Op op) const {
		for (size_t i = 0; i < m_times; ++i) {
			if constexpr (std::is_invocable_v<Op, size_t>) {
				op(i);
			} else {
				op();
			}
		}
	}
};

constexpr Times operator""_times(unsigned long long int n) {
	return Times(n);
}

void whatever();

} // namespace basics

// usage
void foo() {
	using namespace basics;
	5_times([] { whatever(); });
}