a. The old style of representing true/false values used -1 to indicate false and 1 to indicate true.

a. Call the reset member function.
b. Call the flags member function with the ios_base::fmtflags constant as the argument.
c. Save a copy of the fmtflags value returned by calling member function flags before making any format changes,
and then call flags again with that fmtflags value as the argument.
d. You must manually apply each individual format change member function or stream manipulator to restore the
default format state.

c. Save a copy of the fmtflags value returned by calling member function flags before making any format changes,
and then call flags again with that fmtflags value as the argument.