All of the I/O manipulators listed above, with the exception of setw, that only refers to the next output field, affect the stream and all consecutive writing or reading operations use the last specified format until another manipulator is used again.
Some of these manipulators are called without arguments. Examples include boolalpha/noboolalpha or dec/hex/oct. These manipulators are functions that take a single argument, that is a reference to a string, and return a reference to the same stream:
std::ios_base& hex(std::ios_base& str);
Expressions, such as std::cout << std::hex, are possible because both basic_ostream::operator<< and basic_istream::operator>> have special overloads that take a pointer to these functions. ...
