Fall 2006 ECE 575 Midterm Examination
Monday, October 16, 2006
Name: _Answers_
1. C++ (10 points)
(a) A class object is said to be concrete if it can be instantiated. Otherwise, the class is abstract. Three
classes A, B, and C are defined as follows. Pick all the concrete classes. (4 pts):
Class A. (C is not concrete because it doesn’t override virtual void print_out() function which
is the pure virtual function of the base class B.)
#include <string>
#include <vector>
class A
{
std::string Name;
public:
A(const std::string& name): Name(name) {}
};
class B: public A
{
static double CurrentTime;
protected:
B(const std::string& name): A(name) {}
virtual void print_out() = 0;
};
class C: public B
{
Std::vector<B*> Children;
public:
C(const std::string& name): B(name) {}
};
Check the following statements by F for false and T for true. (each 2 pts)
(b) A virtual function can be static. (F)
(c) A destructor can be virtual. (T)
(d) Call-by-value has an advantage over call-by-reference if the memory size of an argument is huge. (F)
2. Standard Template Library (STL) (10 pts)
(a) For making a loop, we need to use the iterator of a STL container. When should we use constant iterator
such as const_iterator? (5 pts) either
(i) if the associated container is a constant one, or
(ii) in a constant function, if the iterator of a STL container is a member data.
(b) We want to model a graph structure G=<V, E> where V is a set of integers, EVV is a set of edges.
Figure 1 shows an instance of the graph. Which STL class among vector, list, set, map, and
multimap is good for representing the edge set EVV? (5 pts): multimap because a vertex can have
its multiple successors such as (1,2) and (1.3).
1
2
3
3
Figure 1. A Graph
1
