3ta zadacha

#include <iostream>
using namespace std;

int HexToDec(char symbol);
void DecToHexPrint(int result);

int main()
{
    char firstSymbol, secondSymbol, thirdSymbol;
    cin >> firstSymbol >> secondSymbol >> thirdSymbol;

    switch (firstSymbol)
    {
    case '+': DecToHexPrint(HexToDec(secondSymbol) + HexToDec(thirdSymbol)); break;
    case '-': DecToHexPrint(HexToDec(secondSymbol) - HexToDec(thirdSymbol)); break;
    case '*': DecToHexPrint(HexToDec(secondSymbol) * HexToDec(thirdSymbol)); break;
    case '/': DecToHexPrint(HexToDec(secondSymbol) / HexToDec(thirdSymbol)); break;
    case '%': DecToHexPrint(HexToDec(secondSymbol) % HexToDec(thirdSymbol)); break;
    default:
        break;
    }
    return 0;
}

int HexToDec(char symbol)
{
    switch (symbol)
    {
    case '0': return 0; break;
    case '1': return 1; break;
    case '2': return 2; break;
    case '3': return 3; break;
    case '4': return 4; break;
    case '5': return 5; break;
    case '6': return 6; break;
    case '7': return 7; break;
    case '8': return 8; break;
    case '9': return 9; break;
    case 'A': return 10; break;
    case 'B': return 11; break;
    case 'C': return 12; break;
    case 'D': return 13; break;
    case 'E': return 14; break;
    case 'F': return 15; break;
    default:
        break;
    }
}

void DecToHexPrint(int result)
{
    if (result == 0)
        return;

    int rem = result % 16;
    result /= 16;
    DecToHexPrint(result);

    if (rem > 9)
        cout << (char)(rem - 10 + 'A');
    else
        cout << rem;
}