Failed attempt to get a quasi-conversion working for a leetcode problem

work on leetcode problem

#include <iostream>
#include <cstdlib>
#include <array>
#include <stdlib.h>

using namespace std;

template <typename A>
using conref = const A&;

template <typename A, size_t sz>
using arry = conref<array<A,sz>> const;

class Solution {
public:
	string convertToTitle(int n) {
		string str;
		Solution::convertToTitle(n, str);

		return str;
	}

private:
	constexpr static const int base{26};

	static void convertToTitle(int n, string& str) {
		auto divRem = div(n, base);

		if (divRem.quot != 0) {
			convertToTitle(divRem.quot, str);
		}

		str += decto26(divRem.rem);
	}

	static inline char decto26(int n) {
		constexpr static const array<char,base> chartConverion {'A', 'B', 'C', 'D',
		'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S',
		'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};

		return chartConverion.at(n);
	}
};

class Solution1 {
public:
	string convertToTitle(int n) {
		string str;
		Solution1::convertToTitle(n, str);

		return str;
	}

private:
	constexpr static const int base{26};

	static void convertToTitle(int n, string& str) {
		auto divRem = div(n, base);

		if (divRem.rem == 0 && divRem.quot != 0) {
			convertToTitle(n - 26, str);
		} else if (divRem.quot != 0) {
			convertToTitle(divRem.quot, str);
		}

		str += decto26(divRem.rem);
	}

	static inline char decto26(int n) {
		constexpr static const array<char,base> chartConverion {'A', 'B', 'C', 'D',
				'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S',
				'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};

		return chartConverion.at(--n);
	}
};

static void testInputConv(arry<int, 8> input, arry<string, 8> expected) {
	Solution sol;
	for (int i = 0; i < input.size(); ++i) {
		auto& in = input.at(i);
		auto result = sol.convertToTitle(in);
		auto& shouldBe = expected.at(i);

		auto isWork = result == shouldBe;
		if (isWork) {
			cout << "CORRECT: ";
		} else {
			cout << "FAILURE: ";
		}

		cout << "Input=" << in << " Result=" << result
			 << " Expected=" << shouldBe << endl;

/*		if (!isWork) {
			return;
		}*/
	}
}

static void testInputConv1(arry<int, 6> input, arry<string, 6> expected) {
	Solution1 sol;
	for (int i = 0; i < input.size(); ++i) {
		auto& in = input.at(i);
		auto result = sol.convertToTitle(in);
		auto& shouldBe = expected.at(i);

		auto isWork = result == shouldBe;
		if (isWork) {
			cout << "CORRECT: ";
		} else {
			cout << "FAILURE: ";
		}

		cout << "Input=" << in << " Result=" << result
				<< " Expected=" << shouldBe << endl;

/*		if (!isWork) {
			return;
		}*/
	}
}

int main() {
	constexpr const size_t sz = 8;
	const array<int, sz> nums{0, 1, 2, 3, 25, 26, 27, 28};
	const array<string, sz> expected{"A", "B", "C", "D", "Z", "BA", "BB", "BC"};

	const array<int, 6> nums1{1, 2, 3, 26, 27, 28};
	const array<string, 6> expected1{"A", "B", "C", "Z", "AA", "AB"};

	testInputConv(nums, expected);
	cout << endl << endl;

	testInputConv1(nums1, expected1);

	return 0;
};