Systemy liczbowy - konwerter

#include <iostream>
#include <cmath>
#include <string>
#include <Windows.h>

std::string changeTheNumber(int inSys, int outSys, std::string inNumber);

int main()
{
/*  while (true) {
        int inputSystem = 0; // System dla liczby wejściowej
        int outputSystem = 0; // System dla liczby wyjściowej
        std::string inputNumber = ""; // Liczba wejściowa
        char allowedChars[] = { '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F' }; // Dozwolone znaki

        do {
            system("cls");
            std::cout << "Podaj system startowy: ";
            std::cin >> inputSystem;
        } while (inputSystem <= 2 && inputSystem >= 16); // Wprowadzenie systemu wejściowego z ograniczeniem (od 2 do 16)

        do {
            system("cls");
            std::cout << "Podaj system docelowy: ";
            std::cin >> outputSystem;
        } while (outputSystem <= 2 && outputSystem >= 16); // Wprowadzenie systemu docelowego z ograniczeniem (od 2 do 16)

        system("cls");

        std::cout << "System startowy: " << inputSystem << std::endl;
        std::cout << "System docelowy: " << outputSystem << std::endl;
        std::cout << "Podaj liczbe do zmiany: ";
        std::cin >> inputNumber; // Wprowadzenie liczby wejściowej

        bool inputNumberIsCorrect = true;

        for (int i = 0; i < inputNumber.length(); i++) { // Sprawdzanie w pętli czy liczba zawiera znaki dozwolone w podanym systemie liczbowym
            for (int z = 0; z < inputSystem; z++) {
                if (inputNumber[i] == allowedChars[z])
                    break;
                else if (inputNumber[i] != allowedChars[z] && z == inputSystem - 1) {
                    inputNumberIsCorrect = false;
                }
            }
        }

        if (!inputNumberIsCorrect) { // Error w przypadku niespełnienia warunków systemu liczbowego
            std::cout << "Twoja liczba jest niedobra";
            Sleep(1000);
            break;
        }

        std::cout << std::endl << changeTheNumber(inputSystem, outputSystem, inputNumber);
        break;
    }
    */

    std::cout << changeTheNumber(10, 16, "1803");
    std::cin.get();
    std::cin.get();

    return 1;
}

std::string changeTheNumber(int inSys, int outSys, std::string inNumber) {
    int decimalInputNumber = 0;
    std::string outNumber = "";

    for (int i = 0; i < inNumber.length(); i++) {
        switch (inNumber[i]) {
        case '0': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 0; break;
        case '1': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 1; break;
        case '2': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 2; break;
        case '3': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 3; break;
        case '4': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 4; break;
        case '5': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 5; break;
        case '6': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 6; break;
        case '7': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 7; break;
        case '8': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 8; break;
        case '9': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 9; break;
        case 'A': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 10; break;
        case 'B': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 11; break;
        case 'C': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 12; break;
        case 'D': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 13; break;
        case 'E': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 14; break;
        case 'F': decimalInputNumber += (int)pow(inSys, inNumber.length() - i - 1) * 15; break;
        }
    }

    int amountOfNumbers = 0;
    for (int z = 0; ; z++) { // Szukanie najwyższej potęgi
        if (pow(outSys, z) > decimalInputNumber) {
            amountOfNumbers = z - 1;
            break;
        }
    }

    while (true) {
        int maxStand = 0;

        for (int z = 1; z < outSys ; z++) { // Szukanie najwyższego mnożnika
            if (pow(outSys, amountOfNumbers) * z > decimalInputNumber) {
                maxStand = z - 1;
                break;
            }
        }

        decimalInputNumber -= (pow(outSys, amountOfNumbers) * maxStand);

        switch (maxStand) {
        case 0: outNumber += '0'; break;
        case 1: outNumber += '1'; break;
        case 2: outNumber += '2'; break;
        case 3: outNumber += '3'; break;
        case 4: outNumber += '4'; break;
        case 5: outNumber += '5'; break;
        case 6: outNumber += '6'; break;
        case 7: outNumber += '7'; break;
        case 8: outNumber += '8'; break;
        case 9: outNumber += '9'; break;
        case 10: outNumber += 'A'; break;
        case 11: outNumber += 'B'; break;
        case 12: outNumber += 'C'; break;
        case 13: outNumber += 'D'; break;
        case 14: outNumber += 'E'; break;
        case 15: outNumber += 'F'; break;
        }

        if (decimalInputNumber == 0 && amountOfNumbers == 0)
            break;
        else
            amountOfNumbers--;
    }

    return outNumber;
}