581325-0 Introduction to Programming, examination 13.11.2000/AW

Write each answer on a separate paper!

You are allowed to use the tools of the Lue-class (or Read-class) for reading the input. This examination is not a direct translation of the Finnish version: question 3 is slightly different.

1. Give short and concise answers to the following:
   • What exactly are object and classes?
   • How can you go through the elements of a matrix one by one? Give an example of an actual program and justify. The size of the matrix is not known.
   • What is the use of the method public String toString()? How do you use it and why?

                                                               (12 points)
   

2. MinMax is a gadget for registering maximum and minimum temperature values. Temperatures are input to the gadget and the user can at any time ask the highest and the lowest temperature that MinMax has received. At the beginning of its use, MinMax sets both the values to 0.0. Also later the gadget can be reset to have zero values. The user can ask, whether MinMax is at the initial state, or if he can rely on the temperature values.

   Implement the gadget as a class MinMax, which has a constructor and the following accessors:

   • public void registerTemperature(double)
   • public double minimum()
   • public double maximum()
   • public void reset()
   • public boolean modified()

                                                               (12 points)
   

3. Explain thoroughly the parameters. What important differences are there between passing int-values as parameters, String objects as parameters, and a SimpleStorage objects as parameters? Give good examples.

                                                               (12 points)
   

4. In political elections one system of calculating the winners is based on proportional representation. In the proportional representation the candidates' so-called comparison figures (double) are computed in the following way.
   • The candidate of a coalition who has been given the most votes is given the total vote number as comparison figure.
   • The candidate who has been given the second most votes is given half the total vote number as comparison figure.
   • The candidate who has been given the third most votes is given a third of the total vote number as comparison figure.
   • ...
   • A higher comparison figure beats a lower one.
   • If two candidates in the same coalition are given the same number of votes, lots are drawn to see who is placed first, and the resulting order decides the comparison figure.
   • If two candidates in different coalitions have been given the same comparison figure, their order is drawn.

   Model a candidate with the class Candidate, with at least the attributes name (String, non-empty), coalition (int, 1-10), and number of votes (int, 0-). The attributes are implemented as fields in the class public.

   Create a program with the help of class Candidate that asks for the data (name, coalition, number of votes) of 903 candidates and checks the accuracy of the data. Then the program computes the comparison figures of the candidates.

   Finally, the program outputs the 85 delegates and their 85 substitutes, along with their data, in the order of their comparison figures. Thus, the comparison figures decide who is elected, and in a tie, lots are drawn.

   For drawing lots, the following practice may be used.

     if (Math.random() < 0.5) 
        // first option
     else 
        // second option
   

                                                               (14 points)