Java Reference
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YClass yObject;
XClass xObject;
a.
The
private
members of
YClass
are
public
members of
XClass
.
True or False?
b.
Mark the following statements as valid or invalid. If a statement is
invalid, explain why.
i.
The following is a valid definition of the method
one
of
YClass
.
public void
one()
{
System.out.println(a + b);
}
ii.
yObject.a = 15;
iii.
xObject.b = 30;
iv.
The following is a valid definition of the method
one
of
XClass
:
public void
one()
{
a = 10;
b = 15;
z = 30;
System.out.println(a + b + z);
}
v.
System.out.println(yObject.a + " " + yObject.b + " "
+ xObject.z);
11.
Assume the declaration of Exercise 10.
a.
Write the definition of the default constructor of
YClass
so that the
instance variables of
YClass
are initialized to
0
.
b.
Write the definition of the default constructor of
XClass
so that the
instance variables of
XClass
are initialized to
0
.
c.
Write the definition of the method
two
of
YClass
so that the instance
variable
a
is initialized to the value of the first parameter of
two
and the
instance variable
b
is initialized to the value of the second parameter of
two
.
12.
Suppose that
class
Three
is derived from
class
Two
and
class
Two
is
derived from
class
One
and each
class
has instance variables. Suppose
that an object of
class
Three
enters its scope, so the constructors of these
classes will execute. Determine the order in which the constructors of these
class
es will execute.
13.
What is the difference between overloading a method name and overriding
a method name?
14.
Name two situations in which you would use the reserved word
super
.
15.
1
0
Suppose that the
class
GradStudent
is derived from the
class
Student
and the
class
Student
has the following method:
public void
printGrades()
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