seekg() is a function in the iostream library (part of the standard library) that allows you to seek to an arbitrary position in a file. It is used in file handling to sets the position of the next character to be extracted from the input stream from a given file. For example :
Input : "Hello World" Output : World
Syntax – There are two syntax for seekg() in file handling :
- istream&seekg(streampos position);
- istream&seekg(streamoff offset, ios_base::seekdir dir);
- position : is the new position in the stream buffer.
- offset : is an integer value of type streamoff representing the offset in the stream’s buffer. It is relative to the dir parameter.
- dir : is the seeking direction. It is an object of type ios_base::seekdir that can take any of the following constant values.
There are 3 direction we use for offset value :
- ios_base::beg (offset from the beginning of the stream’s buffer).
- ios_base::cur (offset from the current position in the stream’s buffer).
- ios_base::end (offset from the end of the stream’s buffer).
If we previously get an end of file on the stream, seekg will not reset it but will return an error in many implementations. – use the clear() method to clear the end of file bit first. This is a relatively common mistake and if seekg() is not performing as expected.
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