CS 112b
Spring 2001
Ileana Streinu

General description

Part I
Basic C++ object oriented programming concepts and basic data structures (60 points)

1. (3 points) What are the values printed by the cout statements in the following program? Write those values on the right of the page next to the program code. Ignore (possible) syntax errors that this (incomplete) program may contain and concentrate on its logic.
   
   main(){
   int a=0, b=1, c=2;
   int choice;
   
   ....
   // the choice variable gets a value somewhere here
   ...
   
   
   switch(choice)
   case 0: func0(a,b,c); cout << a << b << c; break;
   case 1: func1(a,b,c); cout << a << b << c; break;
   case 2: func2(a,b,c); cout << a << b << c; break;
   }
   
   func0(int a, int b, int c)
   {
   a=b;
   b=c;
   c=a;
   }
   
   func1(int &a, int b, int c)
   {
   a=b;
   b=c;
   c=a;
   }
   
   func2(int &a, int &b, int c)
   {
   a=b;
   b=c;
   c=a;
   }
   
   
   
   
   
   
   
   
   
2. (3 points) Write (in the space below) the definition and full code for a C++ function (NOT a main program) to compute the position in a sorted array of n elements where a certain value x is stored, or to insert it (in the appropriate place, i.e. maintaining the property that the resulting array is still sorted), if not already in. The function returns the index of that position, if found, or -1 otherwise (if it was not found but has now been inserted), and it has three parameters: the array, its number of elements and the value x. For each parameter, specify whether it is IN, OUT or IN/OUT.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
3. (2 points) Templates. Extend the previous C++ function to a template, capable of finding the position of an element that is of any type that can be compared with the usual C++ comparison operator < (such as int, char, float).
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
4. (3 points) Functions as parameters. Extend the previous C++ templated function to one capable of working with other data types, which cannot be compared directly with <. Hint: use a function parameter called Compare and rewrite the code accordingly.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
5. (2 points) For the previous situation, give an example of a specific Compare function, which will compare the ages in two records of type CustRec, defined by the following struct:
   
   struct CustRec{
   int id;
   int balance;
   int age;
   }
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
6. Classes. (2 points) Define a class named Book. Each Book has an id (integer), a color (recorded as an integer code) and a size (denoting its number of pages) (integer). In the space below, start writing the class definition, as it would appear in the header file - only the class variables, no functions yet.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   Now finish the definition of the class, as well as make use of this class, by answering the following questions. Use the space below each question to write the answer.
   1. (2 points) For an implementation meant to lead to code reuse and which obeys standard software engineering discipline, the Book class description should be in a file named .........................
      
      
   2. (2 points) For an implementation meant to lead to code reuse and which obeys standard software engineering discipline, the code for the functions in the Book class should be in a file named .........................
      
      
   3. (3 points) Describe the structure of a Makefile for compiling and testing your class Book. The Makefile should obey the rules of structured object-oriented programming, which each class compiled separately. Do not worry about spaces and tabs, but give the right dependencies and separate compilations.
      
      
      
      
      
      
      
      
      
      
   4. (3 points) Describe the structure of a Makefile for compiling and testing the class Book, assuming that you are only writing the testdriver and get the Book class from a library of pre-compiled code. More precisely, you should assume that I have written and compiled the Book class separately, and have made available to you the necessary files for using it, but not the class code (.cpp file).
      
      
      
      
      
      
      
      
   5. (2 points) Write the code for an empty Book constructor. By "empty", I mean that it should be used in constructing an object of this type without giving it any specific values provided by the user - but rather initializing the variables with some defaults values (e.g. all 0's).
      
      
      
      
      
   6. (2 points) Write the code for a Book constructor that takes in three integers (corresponding to id, color and size values) and initializes the current object with those values.
      
      
      
      
      
      
      
      
      
      
   7. (2 points) Write the code for a Print method, which prints on the standard output the values of the three variables of the current Book object.
      
      
      
      
      
      
      
      
      
      
   8. (2 points) Write a statement that declares a variable of type Book.
      
      
      
      
      
   9. (2 points) Write a statement that declares a variable of type Book with initial values (35, 2, 97).
      
      
      
      
      
   10. (2 points) Write a statement that applies the method Print on the object of type Book, which has been created at the previous step.
       
       
       
       
       
   11. (2 points) Write a C++ function to assign a color to the current Book object. Separately, write a statement showing how you would use this function on the variable defined at step 8 above.
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
7. Class templates
   The following class definition restricts the type of information associated to each object of type Point to be an integer.
   
   class Point
   {
   
   public:
   
   Point(); // empty constructor
   Point(int a, int b, int c); // general constructor
   Read(); // read from standard input
   Print(); // print to standard output
   Move(int a, int b); // move a point to a new location
   ChangeInfo(int info); // change the information stored with the point
   
   private:
   
   int x,y; // x and y coordinates
   int information; // other information
   }
   
   • (3 points)Rewrite the class as a template that will accept any data type for information.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
   • (3 points) Give an example of how you would use int as the data type in the declaration of a Point object (i.e. define a variable of type Point, with int as its data type for information)..
     
     
     
     
     
     
     
     
     
     
   • (3 points) Suppose you want to define two variables of type Point: one for which the information stored with the point is a character, the other where this information is a record previously defined with the following struct definition:
     
     struct Label{
     char name[10];
     int nr;
     }
     
     Could you declare both variables using the templated class Point? (Yes/No)
     
     
     If YES, show here the definitions of these variables.
     
     
     
     
     If NO, could you define at least one of these two variables in this way? If yes, give the definition for that variable and a short explanation of why this won't work for the other variable. Otherwise, explain why none of the variables can be defined using the templated class Point.
     
     
     
     
     
     
     
     
     
     
   • (3 points) Define a specialized template for a Point with Label information. You do not have to provide the implementation of all the functions in the class - just the equivalent of the header file.