Chapter 12: Programming Projects ================================ :: 1. You are to create an interactive program that will present the following menu. 0: Quit 1: Add an Event 2: View Events An Event is a class, **CEvent**, that is derived from **CRecord** which is an abstract base class that generically defines records that are held within a document. The **CEvent** class has the following data members. long julianDate; // the date the event is scheduled for long theTime; // the time the event is scheduled for char theEvent[256]; // the statement about the event The abstract base class **CRecord** defines two pure virtual functions for reading input from the disk and for placing data onto the disk. virtual void readRecord( size_t length) const = 0; virtual void writeRecord( size_t length) const = 0; The **CEvent** class implements its own versions of these functions in order to read and write data to disk. This program will create the following C++ classes. CMenu - stores a list of menu items; presents those menu items on the screen; reads a selected menu item and returns an integer value representing the item selected. CDateTime - is an abstract base class that defines those methods needed for date and time handling. This base class acquires the current date and time from the system. One derived class is **CDate** which keeps the date in gregorian and julian formats; holds a string that represents the current date, i.e. "Monday, November 27, 1995". The second derived class is **CTime** which holds the time in hh:mm:ss format and in twenty-four hour format. The base class should declare are pure virtual functions the overload the of the following operators: + : adds a specified number of days to a julian date for **CDate**. + : adds a specified number of minutes to a twenty-four hour time for **CTime**. - : substracts a specified number of days from a julian date for CDate. - : substracts a specified number of minutes from a twenty-four hour time for CTime. CDocument - opens a disk file and stores or retrieves data from the file depending upon which method of the class is called. The constructor is passed the name of the file to open, if the file does not exist then it is created, and the address of a **CRecord** class or derived class. The file is assumed to always be a binary data file. This class has a pointer to the **CRecord** class which holds the address passed as a parameter of the constructor. Overload the following operators: ++ : move to next item in document -- : move to previous item in document + : add a new item to the document - : delete an item from the document Use the pointer to the **CRecord** type to access the correct derived class that knows how to read and write data of the correct type to and from the disk. CView - displays data on the screen, one screen at a time; supports the input of 'N' or 'n' for next screen and 'P' or 'p' for previous screen; also, 'q' or 'Q' for quit which returns back to the main menu. In order for the program to obtain the current date and time from the operating system. The date and time can be obtained by calling the **time()** and **localtime()** functions. The following is a sample program that obtains the date and time from the system: #include #include types.h> #include main() { struct tm *ptr; int nseconds; nseconds = time( (time_t)NULL ); ptr = localtime( &nseconds ); printf("\nptr->tm_sec = %d",ptr->tm_sec); printf("\nptr->tm_min = %d",ptr->tm_min); printf("\nptr->tm_hour = %d",ptr->tm_hour); printf("\nptr->tm_mday = %d",ptr-tm_mday); printf("\nptr->tm_mon = %d",ptr->tm_mon); printf("\nptr->tm_year = %d",ptr->tm_year); printf("\nptr->tm_wday = %d",ptr->tm_wday); printf("\nptr->tm_yday = %d",ptr->tm_yday); printf("\nptr->tm_isdst = %d",ptr->tm_isdst); printf("\n"); } The structure, struct tm, has the following layout: struct tm { int tm_sec; /* seconds after the minute ( 0 - 59 ) */ int tm_min; /* minutes after the hour ( 0 - 59 ) */ int tm_hour; /* hours since midnight ( 0 - 23 ) */ int tm_mday; /* day of the month ( 1 - 31 ) */ int tm_mon; /* month of the year ( 0 - 11 ) */ int tm_year; /* years since 1900 */ int tm_wday; /* days since Sunday ( 0 - 6 ) */ int tm_yday; /* day of the year ( 0 - 365 ) */ int tm_isdst; /* daylight savings time flag */ /* ( 1 = dst ) */ };