Java Reference
In-Depth Information
public
CC(
int
a,
int
b)
//Line 3
{
}
public
CC(
int
a,
int
b,
double
d)
//Line 4
{
}
}
a.
Give the line number containing the constructor that is executed in
each of the following declarations:
i.
CC one =
new
CC();
ii.
CC two =
new
CC(5, 6);
iii.
CC three =
new
CC(2, 8, 3.5);
b.
Write the definition of the constructor in Line 1 so that the instance
variables are initialized to
0
.
c.
Write the definition of the constructor in Line 2 so that the instance
variable
u
is initialized according to the value of the parameter, and the
instance variables
v
and
w
are initialized to
0
.
d.
Write the definition of the constructor in Line 3 so that the instance
variables
u
and
v
are initialized according to the values of the parameters
a
and
b
, respectively, and the instance variable
w
is initialized to
0.0
.
e.
Write the definitions of the constructors in Line 4 so that the instance
variables
u
,
v
, and
w
are initialized according to the values of the
parameters
a
,
b
, and
d
, respectively.
6.
What is a constructor? Why would you include a constructor in a class?
7.
Suppose that
Automobile
is the name of a class. What is the name of a
constructor of this class?
8.
What is the return type of a constructor?
9.
How many default constructors can a class have?
10.
What are some of the differences between a method and a constructor?
11.
Suppose that
c1
and
c2
are reference variables of type
Clock
. What is the
effect of each of the following statements?
a.
c1 =
new
Clock();
b.
c2 =
new
Clock(5, 12, 30);
c.
c1.setTime(3, 24, 36);
d.
c2.setHours(9);
12.
Consider the UML diagram of the class given in Figure 8-25. Suppose that
myState
is a reference variable of the class type given in this figure. Answer
the following questions:
8
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