std::basic_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 <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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最后更新于：2017-12-18