CS 112b
Spring 2002
Ileana Streinu

General description

Part I
Basic C++ object oriented programming concepts and basic data structures (50 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) that would swap the values of three variables a,b,c in a circular fashion, i.e. a will get the value that originally was b's, b will get the original value of c and c gets the original value of a.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
3. (3 points) Write a simple testdriver (main program) to test that the previous function works correctly. Do not use input/output functions: just test everything on a few statically initialized variables.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
4. (3 points) Templates. Extend the previous C++ function (from question 2) to a template, capable of working with data of any type.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
5. (5 points) Functions as parameters. Write a function to find the minimum value stored in an array (which is not sorted). The function should work on data of any type, which may or may not not be compared directly with <. Hint: use templates and a function parameter called Compare.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
6. (4 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;
   }
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
7. Classes. (11 points) Define a class named Robot. Each Robot has an id (integer), a number of legs (recorded as an integer) and a type (denoting whether it runs on batteries or needs an extension cord) (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. (1 points) For an implementation meant to lead to code reuse and which obeys standard software engineering discipline, the Robot class description should be in a file named .........................
      
      
   2. (1 points) For an implementation meant to lead to code reuse and which obeys standard software engineering discipline, the code for the functions in the Robot class should be in a file named .........................
      
      
   3. (1 points) Describe the structure of a Makefile for compiling and testing your class Robot. 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. (1 points) Write the code for an empty Robot 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).
      
      
      
      
      
   5. (1 points) Write the code for a Robot constructor that takes in three integers (corresponding to id, number of legs and type values) and initializes the current object with those values.
      
      
      
      
      
      
      
      
      
      
   6. (1 points) Write the code for a Print method, which prints on the standard output the values of the three variables of the current Robot object.
      
      
      
      
      
      
      
      
      
      
   7. (1 points) Write a statement that declares a variable of type Robot.
      
      
      
      
      
   8. (1 points) Write a statement that declares a variable of type Robot with initial values (35, 6, 1).
      
      
      
      
      
   9. (1 points) Write a statement that applies the method Print on the object of type Robot, which has been created at the previous step.
      
      
      
      
      
   10. (1 points) Write a C++ function to assign a number of legs to the current Robot object. Separately, write a statement showing how you would use this function on the variable defined at step 8 above.
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
8. Class templates(5 points):
   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 ax, int ay, int ainfo); // 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
   }
   Rewrite the class as a template that will accept any data type for information.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
9. (3 points) Sorting Run the Insertion Sort algorithm on the following array of integers:
   
   { 15, 3, 2, 1, 13, 9}
   
   I mean: I do not want to see only the final sorted array!! You should work in stages, following the Insertion Sort algorithm. At each stage, write down how the array currently looks. You do not need to explain what the algorithm does. You do not need to write the code for the algorithm. Just show the array, after each stage.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
10. (3 points) Arithmetic expressions in postfix form. Write the prefix and postfix forms for the following fully parenthesized arithmetic expression: (((4+3)/(6-1))*((2+1)*(3+4)))
    
    
    
    
    
    
    
    
    
    
    
    
11. (3 points) Evaluating arithmetic expressions in postfix form. Find the value of the following arithmetic expression written in postfix form (assumming that we only use one-digit decimal integers): 23+2*42--2/ Apply the algorithm we discussed in class. Trace the execution of the algorithm, and show in sequence how the stack looks like at each step (i.e. after each push and pop). Redraw the stack, do not overwrite.
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
12. (4 points) Stacks for function calls. Trace the status of the stack during the execution of the following program. Redraw the stack after each push and pop, do not overwrite.
    main()
    {
    int x=10,y=1;
    y=func1(x,x);
    cout << x << y << endl;
    }
    
    int func1(int x, int &y)
    {
    y=x-2;
    return (x+3);
    }
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

Part II: hands-on programming (50 points)

• Level 1: the program reads, stores and prints the data.
• Level 2: the information is sorted twice: once by the major, then by the time, and printed after each sorting.
• Level 3: compute the average time per major and print the results.
• Level 4: report the major with the maximum average time for homework, among those reported.

To submit:
1. A file named mid.cpp containing your code.
2. A typescript showing what you have accomplished.
3. (Possibly) a file named unfinished.cpp.
4. All submitted by 10:20 as submit Mid.