std::basic_istream::operator>>
| 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 ); |
(5) | |
| basic_istream& operator>>( bool& value ); |
(6) | |
| basic_istream& operator>>( void*& value ); |
(7) | |
| basic_istream& operator>>( basic_istream& st, std::ios_base& (*func)(std::ios_base&) ); |
(8) | |
| basic_istream& operator>>( basic_istream& st, std::basic_streambuf<CharT,Traits>* sb ); |
(9) | |
1-4) Extracts an integer value by calling num_get::get()
5) Extracts a floating point value by calling num_get::get()
6) Extracts bool value by calling num_get::get()
7) Extracts a generic pointer value by calling num_get::get()
8) Calls func(*this);, where func is an I/O manipulator.
9) Extracts all data 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).
In either case, stores the number of characters extracted in the member variable accessed by subsequent calls to gcount()
Contents |
[edit] Notes
The (1-7) versions of the operator behave as formatted input functions. That is, they construct a sentry object at the beginning that flushes the tie()'d buffers if needed, checks for errors, and extracts and discards all leading whitespace characters unless the ios_base::skipws flag was cleared. The input is attempted only if the sentry object returns true.
The version 8) does not construct the sentry object. The version 9) constructs a sentry object with noskipws set to true.
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)
[edit] 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 |
[edit] Return value
*this
[edit] 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
[edit] See also
| extracts characters and character arrays (function template) | |
| performs stream I/O of strings (function template) | |
| performs stream input and output of bitsets (function) | |
| serializes and deserializes a complex number (function template) | |
| performs stream input and output on pseudo-random number engine (function) | |
| performs stream input and output on pseudo-random number distribution (function) | |
| 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) | |
