When used in an expression out << setiosflags(mask) or in >> setiosflags(mask), sets all format flags of the stream out or in as specified by the mask.

List of all std::ios_base::fmtflags :

• dec - use decimal base for integer I/O
• oct - use octal base for integer I/O
• hex - use hexadecimal base for integer I/O
• basefield - dec|oct|hex|0 useful for masking operations
• left - left adjustment(add fill characters to the right)
• right - right adjustment (adds fill characters to the left)
• internal - internal adjustment (adds fill characters to the internal designated point)
• adjustfield - left|right|internal. Useful for masking operations
• scientific - generate floating point types using scientific notation, or hex notation if combined with fixed
• fixed - generate floating point types using fixed notation, or hex notation if combined with scientific
• floatfield - scientific|fixed|(scientific|fixed)|0. Useful for masking operations
• boolalpha - insert and extract bool type in alphanumeric format
• showbase - generate a prefix indicating the numeric base for integer output, require the currency indicator in monetary I/O
• showpoint - generate a decimal-point character unconditionally for floating-point number output
• showpos - generate a \\+ character for non-negative numeric output
• skipws - skip leading whitespace before certain input operations
• unitbuf flush the output after each output operation
• uppercase - replace certain lowercase letters with their uppercase equivalents in certain output output operations