Lab Exam 8/2/2006

We want to realize a program for collecting data about medical visits. For each visit, the following information is stored:

name of a person (a string),
price of the visit (a double),
result of the visit (a string); if the visit has not been made, the result is null.
duration in minutes (an integer); if the visit has not been made, the duration is -1.

Part 1. Write a class Visit that implements the following methods:

Visit(String n, double p) : constructor that creates an object representing a visit whose name of person is n, whose price is p, and which has not been made yet;
String getName() : that returns the name of the person;
double getPrice() : that returns the price of the visit;
String getResult() : that returns the result of the visit, if it has taken place, and null otherwise;
int getDuration() : that returns the duration of the visit, if it has taken place, and -1 otherwise;
boolean hasTakenPlace() : that checks whether the visit has already taken place;
void visit(String res, int dur) : that changes the status of the visit so that it has taken place, by setting the result of the visit to res and the duration to dur; if the visit had already taken place, the method should do nothing;
String toString() : that returns a string with all the information about the visit.

Example program: TestVisit.Java

Part 2. Write a class UseVisit, client of Visit, that contains the following public static method:

static double averageDuration(Visit[] ar) : that, given an archive ar of visits, represented as an array of visits, calculates the average duration of the visits that have taken place. If there are no visits that have taken place in the archive, the method should return 0.