BASIC-12 十六进制转八进制

#include <iostream>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
using namespace std;

const char HEX[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
const string hexBinary[16] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};
const string octonaryBinary[8] = {"000", "001", "010", "011", "100", "101", "110", "111"};

string toString(int num) {
	string res = "";
	while (num > 0) {
		res += (num % 10) + '0';
		num /= 10;
	}
	reverse(res.begin(), res.end());
	return res;
}
string hexToBinary(string hex) {
	string res = "";
	for (int i = 0; i < hex.length(); i++) {
		for (int j = 0; j < 16; j++) {
			if (hex[i] == HEX[j]) {
				res += hexBinary[j];
				break;
			}
		}
	}
	return res;
}
string binaryToOctonary(string binary) {
	int len = binary.length();
	if (len % 3) {
		reverse(binary.begin(), binary.end());	
		for (int i = 0; i < 3 - (len % 3); i++) {
			binary += '0';
		}
		reverse(binary.begin(), binary.end());
	}
	string res = "";
	string son = "";
	int head = 0;
	for (int i = 0; i < binary.length() / 3; i++) {
		son = binary.substr(head, 3);
		for (int j = 0; j < 8; j++) {
			if (son == octonaryBinary[j]) {
				res += HEX[j];
				break;
			}
		}
		head += 3;
	}
	while (*res.begin() == '0') {
		res.erase(res.begin());
	}
	return res;
}
int main () {
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		string hex;
		cin >> hex;
		cout << binaryToOctonary(hexToBinary(hex)) << "\n";
	}
	return 0;
}