True, we should not be able to read a file after writing in that file without calling the below 

functions.

int fflush ( FILE * stream ); If the given stream was open for writing and the last i/o operation

 was an output operation, any unwritten data in the output buffer is written to the file.

int fseek ( FILE * stream, long int offset, int origin ); Its purpose is to change the file position

 indicator for the specified stream.

void rewind ( FILE * stream ); Sets the position indicator associated with stream to the

 beginning of the file.