Java Reference
In-Depth Information
15
System.out.printf(
"local x in main is %d%n"
, x);
16
17
useLocalVariable();
// useLocalVariable has local x
18
useField();
// useField uses class Scope's field x
19
useLocalVariable();
// useLocalVariable reinitializes local x
20
useField();
// class Scope's field x retains its value
21
22
System.out.printf(
"%nlocal x in main is %d%n"
, x);
23
}
24
25
// create and initialize local variable x during each call
26
public static void
useLocalVariable()
27
{
28
int
x =
25
;
// initialized each time useLocalVariable is called
29
30
System.out.printf(
31
"%nlocal x on entering method useLocalVariable is %d%n"
, x);
32
++x;
// modifies this method's local variable x
33
System.out.printf(
34
"local x before exiting method useLocalVariable is %d%n"
, x);
35
}
36
37
// modify class Scope's field x during each call
38
public static void
useField()
39
{
40
System.out.printf(
41
"%nfield x on entering method useField is %d%n"
, x);
42
x *=
10
;
// modifies class Scope's field x
43
System.out.printf(
44
"field x before exiting method useField is %d%n"
, x);
45
}
46
}
// end class Scope
local x in main is 5
local x on entering method useLocalVariable is 25
local x before exiting method useLocalVariable is 26
field x on entering method useField is 1
field x before exiting method useField is 10
local x on entering method useLocalVariable is 25
local x before exiting method useLocalVariable is 26
field x on entering method useField is 10
field x before exiting method useField is 100
local x in main is 5
Fig. 6.9
|
Scope
class demonstrates field and local-variable scopes. (Part 2 of 2.)
Method
useField
does not declare any local variables. Therefore, when it refers to
x
,
field
x
(line 7) of the class is used. When method
useField
is first called (line 18), it out-
puts the value (
1
) of field
x
(lines 40-41), multiplies the field
x
by
10
(line 42) and outputs
