I can't get this program to run continuously. It works once but when I choose yes to do another one it does it incorrectly

c++

I can't get this program to run continuously. It works once but when I choose yes to do another one it does it incorrectly

//This program will ask user to input a positive integer , then calculates factorial of that number
//Name:
//Date
//             if number is 5, then fact 5 is  5* 4 * 3 * 2 * 1

#include <iostream>
using namespace std;

int main()
{
    int num;      //get user number
    int i;        // controls the loop
    char  resp='y';   // get user wish
    int fact = 1;     // to store factorial of the number
    do
    {
        cout << "Dear user , input a positive number " << endl;
        cin >> num;
        if (num < 0)
            cout << " This is a negative number, i need a positive number" << endl;
        else
        {
            if (num == 0 || num == 1)
                cout << " factorial of this number is ====>  1" << endl;
            else
            {
                for (i = 1; i <= num; i++)
                    fact = fact * i;
                cout << " factorial of this number is ====>  " << fact<<endl;
            }
        }
        cout << "Would you like to try my program again?   y, Y , any other character , terminates the program" << endl;
        cin >> resp;
    } while (resp == 'Y' || resp == 'y');

    system("pause");
    return 0;
}