basic_istream& unget(); |
Makes the most recently extracted character available again.
First clears | (since C++11) |
Then the function behaves as UnformattedInputFunction
. After constructing and checking the sentry object, if any ios_base::iostate
flags are set, the function sets failbit
and returns. Otherwise, calls rdbuf()->sungetc()
.
If rdbuf()->sungetc()
returns Traits::eof()
, calls setstate(badbit)
.
In any case, sets the gcount()
counter to zero.
Parameters
(none).
Return value
*this
.
Exceptions
failure
if an error occurred (the error state flag is not goodbit
) and exceptions()
is set to throw for that state.
If an internal operation throws an exception, it is caught and badbit
is set. If exceptions()
is set for badbit
, the exception is rethrown.
Example
#include <sstream> #include <iostream> int main() { std::istringstream s1("Hello, world."); char c1 = s1.get(); if (s1.unget()) { char c2 = s1.get(); std::cout << "Got: " << c1 << " got again: " << c2 << '\n'; } }
Output:
Got: H got again: H
See also
moves the next pointer in the input sequence back by one (public member function of std::basic_streambuf ) | |
extracts characters (public member function) | |
reads the next character without extracting it (public member function) | |
puts character into input stream (public member function) |
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