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Repositioning a File Pointer

Repositioning a File Pointer

The fseek() function provides random file access. It’s declared in as follows:

 int fseek(FILE *fstream, int offset, int whence);

The function sets the file pointer associated with fstream to a new position that is offsetbytes from the location specified by whence. The argument whence can have one of these values:

 SEEK_SET // file's beginningSEEK_CUR // current file positionSEEK_END // end of file

In the following example, fseek() is used to calculate a file’s size in a portable manner:

 long file_size (FILE *f);{ long cur_pos, length; cur_pos = ftell(f) fseek(f, 0, SEEK_END); // set pointer to end of file length=ftell(f); // offset in bytes from file's beginning fseek(f, cur_pos, SEEK_SET); // restore original position return length;}

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