Program: Write a program to computerize the billing system of a hospital.

Part 1: Design the class doctorType, inherited from the class personType, with an additional data member to store a doctor's specialty.

Add suitable constructors and member functions to initialize, access, and manipulate the data members.

Part 2: Design the class billType with data members to store a patient's ID and a patient's hospital charges (such as pharmacy charges for medicine, doctor's fee, and room charges).

Add suitable constructors and member functions to initialize, access, and manipulate the data members.

Part 3: Design the class patientType, inherited from the class personType, defined in Chapter 10, with additional data members to store a patient's ID, age, date of birth, attending physician's name, the date when the patient was admitted in the hospital, and the date when the patient was discharged from the hospital.

Part 4: Use the class dateType to store the date of birth, admit date, discharge date, and the class doctorType to store the attending physician's name.

You need to computerize the billing system of a hospital and manipulate the data members. It must compile with no errors and follow the directions.