private void writeTxtBxFactors(Int64 intToFactor) { PrimeFactorization pF = new PrimeFactorization(intToFactor); List <Int64> li = pF.Factor(); string f = ""; foreach (Int64 i in li) { if (f == "") { f = i.ToString(); } else { f = f + "*" + i; } } txtBxFactors.Text = f; }