std::basic_istream::unget
basic_istream& unget(); | | |
|---|
使最近提取的字符再次可用。
First clears eofbit. | (since C++11) |
|---|
然后，该函数表现为UnformattedInputFunction.在构造和检查哨兵对象(如果有的话)之后ios_base::iostate设置标志，则设置函数集。failbit然后回来。否则，打电话rdbuf()->sungetc()...
如果rdbuf()->sungetc()回报Traits::eof()，电话setstate(badbit)...
在任何情况下，设置gcount()对零。
参数
%280%29
返回值
*this...
例外
failure如果发生错误%28，则错误状态标志不是goodbit29%和exceptions()将被抛向那个州。
如果内部操作抛出异常，则会捕获该操作，并且badbit已经设定好了。如果exceptions()设置为badbit，异常将被重新抛出。
例
二次
#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';
}
}二次
产出：
二次
Got: H got again: H二次
另见
sungetc | moves the next pointer in the input sequence back by one (public member function of std::basic_streambuf) |
|---|---|
get | extracts characters (public member function) |
peek | reads the next character without extracting it (public member function) |
putback | puts character into input stream (public member function) |
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