#!/usr/bin/env cscript
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void
cast_column_index(char *column_index_string, int column_index) {
	int needle_column_index_string = 0;
	char *reverse_column_index_string;

	memset(column_index_string, '\0', strlen(column_index_string));

	while (column_index > 0) {
		column_index_string[needle_column_index_string] = column_index % (26 + 1) + 'A' - 1;

		if (column_index_string[needle_column_index_string] == 'A' - 1) {
			column_index_string[needle_column_index_string]++;
		}

		column_index /= 26 + 1;
		needle_column_index_string += 1;
	}

	reverse_column_index_string = strdup(column_index_string);

	for (; needle_column_index_string >= 0; needle_column_index_string--) {
		reverse_column_index_string[needle_column_index_string] = column_index_string[strlen(column_index_string) - needle_column_index_string - 1];
	}

	strcpy(column_index_string, reverse_column_index_string);
	free(reverse_column_index_string);
}

int
main(int argc, char *argv[]) {
	char column_index_string[3 + 1] = {0};
	cast_column_index(column_index_string, 1);
	printf("1 → %s / A\n", column_index_string);
	cast_column_index(column_index_string, 25);
	printf("25 → %s / Y\n", column_index_string);
	cast_column_index(column_index_string, 26);
	printf("26 → %s / Z\n", column_index_string);
	cast_column_index(column_index_string, 27);
	printf("27 → %s / AA\n", column_index_string);
	cast_column_index(column_index_string, 52);
	printf("52 → %s / AY\n", column_index_string);
	cast_column_index(column_index_string, 53);
	printf("53 → %s / AZ\n", column_index_string);
	cast_column_index(column_index_string, 54);
	printf("54 → %s / BA\n", column_index_string);
	return 0;
}