std::basic_ostream::operator<<

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basic_ostream& operator<<( short value ); basic_ostream& operator<<( unsigned short value );	(1)

basic_ostream& operator<<( int value ); basic_ostream& operator<<( unsigned int value );	(2)

basic_ostream& operator<<( long value ); basic_ostream& operator<<( unsigned long value );	(3)

basic_ostream& operator<<( long long value ); basic_ostream& operator<<( unsigned long long value );	(4)	(since C++11)

basic_ostream& operator<<( float value ); basic_ostream& operator<<( double value ); basic_ostream& operator<<( long double value );	(5)

basic_ostream& operator<<( bool value );	(6)

basic_ostream& operator<<( const void* value );	(7)

basic_ostream& operator<<( std::basic_streambuf<CharT, Traits>* sb);	(8)

basic_ostream& operator<<( basic_ostream& st, std::ios_base& (func)(std::ios_base&) ); basic_ostream& operator<<( basic_ostream& st, std::basic_ios<CharT,Traits>& (func)(std::basic_ios<CharT,Traits>&) ); basic_ostream& operator<<( basic_ostream& st, std::basic_ostream& (*func)(std::basic_ostream&) );	(9)

Inserts data into the stream.

1-2) Behaves as an FormattedOutputFunction. After constructing and checking the sentry object, if value is short or int, then casts it to unsigned short or unsigned int if ios_base::flags() & ios_base::basefield is ios_base::oct or ios_base::hex. After that, casts to long in any case and outputs as in (3). If value is unsigned short or unsigned int, casts to unsigned long and outputs as in (3).

3-7) Behaves as an FormattedOutputFunction. After constructing and checking the sentry object, inserts an integer, floating point, boolean or generic pointer value by calling num_put::put(). If the end of file condition was encountered during output (put().failed() == true), sets ios::badbit.

8) Behaves as an UnformattedOutputFunction. After constructing and checking the sentry object, checks if sb is a null pointer. If it is, executes setstate(badbit) and exits. Otherwise, extracts characters from the input sequence controlled by sb and inserts them into *this until one of the following conditions are met:

end-of-file occurs on the input sequence;
inserting in the output sequence fails (in which case the character to be inserted is not extracted);
an exception occurs (in which case the exception is caught).

If no characters were inserted, executes setstate(badbit). If an exception was thrown while extracting, sets failbit

9) Calls func(*this);. This overload is used to implement output I/O manipulators such as std::endl.

#include <iostream>
#include <iomanip>
#include <sstream>
int main()
{
    std::istringstream input(" \"Some text.\" ");
    volatile int n = 42;
    double f = 3.14;
    bool b = true;;
    std::cout << n   // int overload
              << ' ' // non-member overload
              << std::boolalpha << b // bool overload
              << " " // non-member overload
              << std::fixed << f // double overload
              << input.rdbuf() // streambuf overload
              << &n // bool overload
              << std::endl; // function overload
}

Output:

42 true 3.140000 "Some text." true

[edit] See also


operator<<(std::basic_ostream)	inserts character data (function)

operator<< operator>>	performs stream I/O of strings (function template)

operator<< operator>>	performs stream input and output of bitsets (function)

operator<< operator>>	serializes and deserializes a complex number (function template)

operator<< operator>>	performs stream input and output on pseudo-random number engine (function)

operator<< operator>>	performs stream input and output on pseudo-random number distribution (function)

put	inserts a character (public member function)

write	inserts blocks of characters (public member function)

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)

std::basic_ostream::operator<<

Contents

[edit] Parameters

[edit] Return value

[edit] Notes

[edit] Example

[edit] See also

value	-	integer, floating-point, boolean, or pointer value to insert
func	-	function to call
sb	-	pointer to the streambuffer to read the data from