Binary Conversion

#include <iostream>
#include <String>

using namespace std;

void DecToBin(int num, int base);
double rem;
int final[99];
int i = 0.0;

int main()
{
    double DecimalNum, base;
    cout << "Welcome to Binary conversion program!" << endl;

    cout << "Enter your base: ";
    cin >> base;
            while (base < 2 || base > 35)
            {
            cout << "Between 2~35 please :)" << endl;
            while(!(cin >> base)) // Loops that goes on until cin fails
        {

            cin.clear(); // if fails, clear the failed flag.
            while(cin.get() != '\n'){} // A loop the cleans out anything that is left over in the input stream.

            cout << "Only numbers please: " << endl << "What's the base again? " <<endl;// Output failed prompt. And requires only numbers
        }
            }


    cout << "Enter number in decimal: ";
    cin >> DecimalNum;

    DecToBin(DecimalNum, base);
    return 0;
}

    void DecToBin(int num, int base)
{
    while (num != 0)
    {
        rem = (num%base);

        final[i] = rem;
        i++;

        num = num/base;
    }
            for (i--; i>-1; i--)
            {
                if (final[i]<10) // if the remainder goes up to 10 then it changes the value to letters..

                cout << final[i];

                else

                cout << char(final[i]-10+'a');
            }
            num = 1;
            cout << endl;

    }