Fibonnaci

// fibonacci - just to see if i know what the hell I'm doing
#include <iostream>
using namespace std;

int main()
{
    int current, previous1, previous2, nthFibonacci;
    bool done = false;

    cout << "Enter the first two numbers of the fibonacci: ";
    cin >> previous1 >> previous2;
    cout << "Enter the nth Fibonacci you want: ";
    cin >> nthFibonacci;
    cout << endl;

    if (!cin.good())
    {
        cin.clear();
        cin.ignore(100, '\n');
        cout << "Numbers only you letter-aholic!" << endl;
    }
    else if(previous1 <= 0 || previous2 <= 0 || nthFibonacci <= 0)
    {
        cout << "Enter numbers over 0 for all prompts." << endl;
    }
    else
    {
        cout << previous1 << " " << previous2 << " ";

        while (!done)
        {
            if (nthFibonacci == 1)
            {
                current = previous1;
            }
            else if (nthFibonacci == 2)
            {
                current = previous2;
            }
            else
            {
                int counter = 3;
                while (counter <= nthFibonacci)
                {
                    current = previous1 + previous2;
                    previous1 = previous2;
                    previous2 = current;
                    cout << current << " ";
                    counter++;
                }
            }
            cout << "\nThe " << nthFibonacci << "th fibonacci is : " << current << endl;
            done = true;
        }
    }
    return 0;
}