My code does not return same value in cout dunction and stored in a variable

If i enter the fallowing:

 0 0 0 23 2 20 3

I expect

0, 0, 0
11, 1, 10
23, 2, 20

but i recive

0, 0, 0
12, 1, 10
23, 2, 20

---

double  r1, g1, b1, r2, g2, b2, n, r, g, b;
cin >> r1 >> g1 >> b1 >> r2 >> g2 >> b2 >> n;
r = r2 - r1;
g = g2 - g1;
b = b2 - b1;
cout << r1 << ", " << g1 << ", " << b1 << endl;
//...
n -= 2;
//cout<<trunc(r / (1 + 1));
for (double  i = 1; i <= n; i++)
{
    cout << abs(trunc(r / (i + 1))) << endl;
    r -= abs(trunc(r / (i + 1)));
    cout << r << endl;

    b -= abs(trunc(b / (i + 1)));
    g -= abs(trunc(g / (g + 1)));
    cout << r << ", " << g << ", " << b << endl;
}







cout << r2 << ", " << g2 << ", " << b2;