basic_istream& operator>>( short& value ); basic_istream& operator>>( unsigned short& value ); | (1) | |
basic_istream& operator>>( int& value ); basic_istream& operator>>( unsigned int& value ); | (2) | |
basic_istream& operator>>( long& value ); basic_istream& operator>>( unsigned long& value ); | (3) | |
basic_istream& operator>>( long long& value ); basic_istream& operator>>( unsigned long long& value ); | (4) | (since C++11) |
basic_istream& operator>>( float& value ); basic_istream& operator>>( double& value ); basic_istream& operator>>( long double& value ); | (5) | |
basic_istream& operator>>( bool& value ); | (6) | |
basic_istream& operator>>( void*& value ); | (7) | |
basic_istream& operator>>( std::ios_base& (*func)(std::ios_base&) ); | (8) | |
basic_istream& operator>>( std::basic_ios<CharT,Traits>& (*func)(std::basic_ios<CharT,Traits>&) ); | (9) | |
basic_istream& operator>>( basic_istream& (*func)(basic_istream&) ); | (10) | |
basic_istream& operator>>( std::basic_streambuf<CharT,Traits>* sb ); | (11) |
1-4) Behaves as a
FormattedInputFunction
. After constructing and checking the sentry object, which may skip leading whitespace, extracts an integer value by calling std::num_get::get()
5) Behaves as a
FormattedInputFunction
. After constructing and checking the sentry object, which may skip leading whitespace, extracts a floating point value by calling std::num_get::get()
6) Behaves as a
FormattedInputFunction
. After constructing and checking the sentry object, which may skip leading whitespace, extracts bool
value by calling std::num_get::get()
7) Behaves as a
FormattedInputFunction
. After constructing and checking the sentry object, which may skip leading whitespace, extracts a generic pointer value by calling std::num_get::get()
8-10) Calls
func(*this);
, where func
is an I/O manipulator. 11) Behaves as an
UnformattedInputFunction
. After constructing and checking the sentry object, extracts all data from the input stream and stores it to sb
. The extraction stops if 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, and only rethrown if
failbit
is enabled inexceptions()
).
gcount()
. If sb
is a null pointer of it no characters were inserted into sb
, calls setstate(failbit)
(which may throw std::ios_base::failure
if enabled). If extraction fails (e.g. if a letter was entered where a digit is expected), value is left unmodified and failbit is set. | (until C++11) |
If extraction fails, zero is written to value and failbit is set. If extraction results in the value too large or too small to fit in value , std::numeric_limits<T>::max() or std::numeric_limits<T>::min() is written and failbit flag is set. | (since C++11) |
Parameters
value | - | reference to an integer or floating-point value to store the extracted value to |
func | - | pointer to I/O manipulator function |
sb | - | pointer to the streambuffer to write all the data to |
Return value
1-9,11)
*this
10)
func(*this)
Example
#include <iostream> #include <iomanip> #include <sstream> int main() { std::string input = "41 3.14 false hello world"; std::istringstream stream(input); int n; double f; bool b; stream >> n >> f >> std::boolalpha >> b; std::cout << "n = " << n << '\n' << "f = " << f << '\n' << "b = " << std::boolalpha << b << '\n'; // extract the rest using the streambuf overload stream >> std::cout.rdbuf(); std::cout << '\n'; }
Output:
n = 41 f = 3.14 b = false hello world
See also
extracts characters and character arrays (function template) | |
performs stream input and output on strings (function template) | |
performs stream input and output of bitsets (function template) | |
serializes and deserializes a complex number (function template) | |
performs stream input and output on pseudo-random number engine (function template) | |
performs stream input and output on pseudo-random number distribution (function template) | |
extracts blocks of characters (public member function) | |
extracts already available blocks of characters (public member function) | |
extracts characters (public member function) | |
extracts characters until the given character is found (public member function) |
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