Arithmetic Inserter Operator <<

Provides formatted insertion of types into a stream.

  basic_ostream<charT, traits>& operator<<(short n)
  basic_ostream<charT, traits>& operator<<(unsigned short n)
  basic_ostream<charT, traits>& operator<<(int n)
  basic_ostream<charT, traits>& operator<<(unsigned int n)
  basic_ostream<charT, traits>& operator<<(long n)
  basic_ostream<charT, traits>& operator<<(unsigned long n)
  basic_ostream<charT, traits>& operator<<(float f)
  basic_ostream<charT, traits>& operator<<(double f)
  basic_ostream<charT, traits>& operator<<(long double f)

Remarks

Converts an arithmetic value. The formatted values are converted as if they had the same behavior of the fprintf() function.

In most cases *this is returned unless failure, in which case set state(failbit) is called.

Table 1. Output states and stdio equivalents.
Output State	stdio equivalent
Integers
(flags() & basefield) == oct	%o
(flags() & basefield) == hex	%x
(flags() & basefield) != 0	%x
Otherwise
signed integral type	%d
unsigned integral type	%u
Floating Point Numbers
(flags() & floatfield) == fixed	%f
(flags() & floatfield) == scientific (flags() & uppercase) != 0	%e %E
Otherwise
(flags() & uppercase) != 0	%g %G
An integral type other than a char type
(flags() & showpos) != 0 (flags() & showbase) != 0	+ #
A floating point type
(flags() & showpos) != 0 (flags() & showpoint) != 0	+ #

For any conversion, if width() is non-zero then a field with a conversion specification has the value of width().

For any conversion, if (flags() and fixed) !=0 or if precision() >0 the conversion specification is the value of precision().

For any conversion, padding behaves in the following manner.

Table 2. Conversion state and stdio equivalents
State	Justification	stdio equivalent
(flags()& adjustfield) == left	left	space padding
(flags() & adjustfield) == internal	Internal	zero padding
Otherwise	right	space padding

The ostream insertion operators are overloaded to provide for insertion of most predefined types into an output stream. They return a reference to the basic stream object so they may be used in a chain of statements to input various types to the same stream.