Computer Science - Object Oriented Programming Using C++ - Discussion

3what is mean by format flag? Explain, please.

What is meant by format flag?

Realy, I want to know what is format flag?

cout and cin contain several single-bit flags for format control. They are named in an enum in class ios as:

ios::skipws // skips whitspace on input
ios::left // left justification
ios::right // right justifiction
ios::internal // pads after sign or base character
ios::dec // decimal format for integers
ios::oct // octal format for integers
ios::hex // hex format for integers
ios::showbase // show the base character for octal or hex
ios::showpoint // show the decimal point for all floats
ios::uppercase // uppercase A-F for hex
ios::showpos // show +ve sign for numbers
ios::scientific // use exponential notation
ios::fixed // used oridnary decimal notation
ios::unitbuf // flush the buffer

These flags can be set with the member function setf. e.g.

cout.setf(ios::showpos);

They can be or'd together:
cout.setf(ios::showpos | ios::uppercase);
or some bits can be unset while one is being set:
cout.setf(ios::oct, ios::dec | ios::oct | ios::hex);

This sets the bit for oct, after unsetting the bits for oct, dec and hex, ensuring that only one of the bits is turned on.
unsetf turns bits off:
cout.unsetf(ios::showpos);

Please, be clear what are format flags?

Can anyone tell me what is format flags, and what is its use?

It is actually very beneficial. Thanks @Sunder.

What are format flags? Please describe it in detail.

It is denoted by the virtual number.

Thanks @Sundar. It helps me. :)