std::basic_istream::operator>>
性病：基本[医]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 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%29表现为FormattedInputFunction.在构造和检查哨兵对象(可能跳过前导空格)之后，通过调用std::num_get::get()
5%29表现为FormattedInputFunction.在构造和检查哨兵对象(可能跳过前导空格)之后，通过调用std::num_get::get()
6%29表现为FormattedInputFunction.在构造和检查哨兵对象(可能跳过前导空格)之后，提取bool通过调用std::num_get::get()
7%29表现为FormattedInputFunction.在构造和检查哨兵对象(可能跳过前导空格)之后，通过调用std::num_get::get()
8-10%29次电话func(*this，在哪里func是I/O操作器。
11%29表现为UnformattedInputFunction.在构造和检查哨兵对象之后，从输入流中提取所有数据并将其存储到sb.如果符合下列条件之一，则停止提取：
- 文件结束发生在输入序列上；
- 在输出序列中插入失败%28，在这种情况下，要插入的字符不会提取%29；
- 异常发生在%28，在这种情况下，异常将被捕获，并且只有在以下情况下才会重新引发
failbit中启用exceptions()29%。
在任何一种情况下，都存储通过后续调用访问的成员变量中提取的字符数。gcount().如果sb是一个空指针，它没有插入字符。sb，电话setstate(failbit)%28std::ios_base::failure如果启用%29。
| 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) |
参数
| 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 |
返回值
1-9-9 11%29*this
10%29func(*this)
例
二次
#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';
}
二次
产出：
二次
n = 41
f = 3.14
b = false
hello world
二次
另见
| operator>>(std::basic_istream) | extracts characters and character arrays (function template) |
|---|---|
| operator<<operator>> | performs stream input and output on strings (function template) |
| operator<<operator>> | performs stream input and output of bitsets (function template) |
| operator<<operator>> | serializes and deserializes a complex number (function template) |
| operator<<operator>> | performs stream input and output on pseudo-random number engine (function template) |
| operator<<operator>> | performs stream input and output on pseudo-random number distribution (function template) |
| read | extracts blocks of characters (public member function) |
| readsome | extracts already available blocks of characters (public member function) |
| get | extracts characters (public member function) |
| getline | extracts characters until the given character is found (public member function) |
| from_chars (C++17) | converts a character sequence to an integer or floating-point value (function) |
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