PChar(case=2, alpha=2) : generate random characters, case{0: lowercase, 1: uppercase, 2: both}, alpha{0: alpha, 1: nonalpha, 2: both}
PChar(case=2, alpha=2) : generate random characters, case{0: lowercase, 1: uppercase, 2: both}, alpha{0: alpha, 1: nonalpha, 2: both}