CSE2050 Spring 2004 Final Exam, open book, open notes. Name ________________

1.  True or false?  Circle T or F (2 pts each).

ANSWERS (with explanations in parenthesis)

T  std is a namespace.
F  cout is a class.
   (it is an object)
T  The . operator has higher precedence than =
F  10 * 0.1 == 1 exactly.
   (due to roundoff error, 0.1 has no exact representation)
F  The following sorts array x: int x[10]; sort(x.begin(), x.end());
   (sort(x, x+10);)
F  An uncaught exception has no effect on program execution.
   (the program terminates)
F  If a and b are vectors, then copy(a.begin(), a.end(), b.begin());
       changes b.size() to a.size().
   (if b is smaller then copy() writes out of bounds)
F  Expressions can only be passed to a function by reference.
   (they can only be passed by value or const reference)
F  map<vector<int>,int>::iterator is a random access iterator type.
   (bidirectional)
F  If m is a map and m[x] == y then m.find(x) == y
   (find() returns an iterator, m.find(x)->second == y)
T  swap() is a templated function in <algorithm>.
T  An algorithm that accepts input iterators will also accept pointers.
T  If all base class constructors require arguments, then all constructors
       in derived classes must have initialization lists.
F  If X and X::Y are classes, then X::f() may access protected data in X::Y
T  If x1 and x2 are type X, then x1.f() may access private data in x2.
T  The following may cause a segmentation fault: char *s; cin >> s;
   (because s points to a random place in memory where cin writes)
F  delete p; throws bad_alloc if p == 0
   (delete 0; has no effect)
T  Every class has at least one constructor even if you don't write any.
   (it has a copy constructor, also a default constuctor if you don't write one)
F  If X is a class, then X::X():f(0){} means to call function f with
       argument 0 whenever an X object is created.
   (it means to initialize the data member or base class f with 0)
F  A constructor taking no arguments defines an implicit conversion.
   (but a constructor taking 1 argument does)
F  A default assignment operator does a bitwise copy of all data members.
   (it uses the appropriate assignment operator for each data member)
F  A derived class should initialize protected inherited data members.
   (the base class should do this)
F  A derived class should always declare a virtual destructor.
   (but a base class with virtual functions should)
T  All code in a header file should be templated or inlined.
F  A reference of type T& is not allowed if T has pure virtual functions.
   (in fact this is normal practice)


2.  Write an interface for class Person.  Add member functions required
by the rule of 3 (if any) to both classes (50 pts).

class Person: public Printable {
  string* name;  // 2 element array containing first and last name
public:
  void print() const {cout << name[0] << " " << name[1];}
  Person(const char* first, const char* last=""): name(new string[2]) {
    name[0]=first; name[1]=last;
  }

  // ANSWER
  ~Person() {delete[] name;}  // don't forget the []

  Person(const Person& p): name(new string[2]) {  // copy constructor
    name[0] = p.name[0];
    name[1] = p.name[1];
  }

  // No need to check for assignment to self since size doesn't change
  Person& operator = (const Person& p) {
    name[0] = p.name[0];
    name[1] = p.name[1];
    return *this;
  }
};

// Interface (would normally appear before class Person)
class Printable {
public:
  virtual void print() const = 0;
  virtual ~Printable() {}
};