A busy week for earnings also included reports from Alphabet Inc GOOGL.O and Microsoft Corp MSFT.O after the bell. By Caroline Valetkevitch NEW YORK, July 26 (Reuters) - U.S. stocks ended sharply lower Tuesday as a profit warning by Walmart dragged down retail shares and exceptionally weak consumer confidence data also fueled fears about spending. On Tuesday, data showed U.S. consumer confidence dropped to nearly a 1-1/2-year low in July amid persistent worries about higher inflation and rising interest rates.