A file pointer is a pointer to a structure, which contains information about the file, including its name, current address of the file in the memory, whether the file is being read or written, and whether errors or end of the file have occurred. The user does not need to Know the details, because the definitions obtained from stdio.h include a structure declaration called FILE. The only declaration needed for a file pointer is symbolized by FILE *fp; This says that fp is the file pointer that points to a FILE structure. Opening a file: The fopen() function opens a stream for use and links a file with that stream. A file pointer associated with that file is then returned by the fopen() function. Most often the file is a disk file. The prototype for the fopen() function is FILE *fopen( const char * filename, const char *mode); Where filename is a pointer to a string of characters that make up a valid file name and can also include a...