std::basic_istream::tellg
性病:基本[医]iStream::tellg
pos_type tellg( | | |
---|
返回当前关联的输入位置指示符。streambuf
对象。
表现为UnformattedInputFunction,除了gcount()不受影响。在构造和检查哨兵对象之后,如果fail() == true、回报pos_type(-1).否则,返回rdbuf()->pubseekoff(0,std::ios_base::cur,std::ios_base::in)...
参数
%280%29
返回值
GET指针的当前成功位置,pos_type(-1)
在失败的时候。
例外
failure
如果发生错误%28,则错误状态标志不是goodbit
29%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 <iostream>
#include <string>
#include <sstream>
int main()
{
std::string str = "Hello, world";
std::istringstream in(str
std::string word;
in >> word;
std::cout << "After reading the word \"" << word
<< "\" tellg() returns " << in.tellg() << '\n';
}
二次
产出:
二次
After reading the word "Hello," tellg() returns 6
二次
另见
seekoff virtual | repositions the file position, using relative addressing (virtual protected member function of std::basic_filebuf) |
---|---|
seekoff virtual | repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function of std::basic_stringbuf) |
seekoff virtual | repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function of std::strstreambuf) |
seekg | sets the input position indicator (public member function) |
tellp | returns the output position indicator (public member function of std::basic_ostream) |
seekp | sets the output position indicator (public member function of std::basic_ostream) |
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