C++ basic_ios Library - seekg


Description

It is used to set position in input sequence.

Declaration

Following is the declaration for std::basic_istream::seekg.

(1)	 basic_istream& seekg (pos_type pos);
(2)	 basic_istream& seekg (off_type off, ios_base::seekdir way);

Parameters

  • pos − New absolute position within the stream (relative to the beginning).

  • off − Offset value, relative to the way parameter.

  • way − Object of type ios_base::seekdir.

Return Value

Returns the basic_istream object (*this).

Exceptions

Basic guarantee − if an exception is thrown, the object is in a valid state.

Data races

Modifies the stream object.

Example

In below example for std::basic_istream::seekg.

#include <iostream>     
#include <fstream>      

int main () {
   std::ifstream is ("test.txt", std::ifstream::binary);
   if (is) {
      is.seekg (0, is.end);
      int length = is.tellg();
      is.seekg (0, is.beg);
    
      char * buffer = new char [length];
    
      is.read (buffer,length);
      is.close();
    
      std::cout.write (buffer,length);

      delete[] buffer;
   }
   return 0;
}
istream.htm
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