Java Reference
In-Depth Information
Pass-by-value (here
the value is 5)
Stack
Heap
Space required for the
printArea
method
int times:
5
Circle c:
Pass-by-value
(here the value is
the reference for
the object)
reference
Space required for the
main
method
int n:
5
myCircle:
A
Circle
object
reference
F
IGURE
8.18
The value of
n
is passed to
times
, and the reference to
myCircle
is passed to
c
in the
printAreas
method.
8.23
✓
✓
Describe the difference between passing a parameter of a primitive type and passing
a parameter of a reference type. Show the output of the following programs:
Check
Point
public class
Test {
public static void
main(String[] args) {
Count myCount =
new
Count();
int
times =
0
;
public class
Count {
public int
count;
public
Count(
int
c) {
count = c;
for
(
int
i =
0
; i <
100
; i++)
increment(myCount, times);
}
public
Count() {
count =
1
;
System.out.println(
"count is "
+ myCount.count);
System.out.println(
"times is "
+ times);
}
}
}
public static void
increment(Count c,
int
times) {
c.count++;
times++;
}
}
8.24
Show the output of the following program:
public class
Test {
public static void
main(String[] args) {
Circle circle1 =
new
Circle(
1
);
Circle circle2 =
new
Circle(
2
);
swap1(circle1, circle2);
System.out.println(
"After swap1: circle1 = "
+
circle1.radius +
" circle2 = "
+ circle2.radius);
swap2(circle1, circle2);
System.out.println(
"After swap2: circle1 = "
+
circle1.radius +
" circle2 = "
+ circle2.radius);
}
public static void
swap1(Circle x, Circle y) {
Circle temp = x;
x = y;
y = temp;
