Java Reference
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public static int method( int y) {
return y;
}
}
5.19
Given two method definitions,
public static double m( double x, double y)
public static double m( int x, double y)
tell which of the two methods is invoked for:
a. double z = m( 4 , 5 );
b. double z = m( 4 , 5.4 );
c. double z = m( 4.5 , 5.4 );
5.9 The Scope of Variables
The scope of a variable is the part of the program where the variable can be
referenced.
Key
Point
Section 2.5 introduced the scope of a variable. This section discusses the scope of vari-
ables in more details. A variable defined inside a method is referred to as a local variable.
The scope of a local variable starts from its declaration and continues to the end of the
block that contains the variable. A local variable must be declared and assigned a value
before it can be used.
A parameter is actually a local variable. The scope of a method parameter covers the entire
method. A variable declared in the initial-action part of a for -loop header has its scope in
the entire loop. However, a variable declared inside a for -loop body has its scope limited
in the loop body from its declaration to the end of the block that contains the variable, as
shown in Figure 5.5.
scope of a variable
local variable
public static void method1() {
.
.
for ( int
i
= 1 ; i < 10 ; i++) {
.
.
The scope of i
int
j
;
.
.
.
The scope of j
}
F IGURE 5.5 A variable declared in the initial action part of a for -loop header has its scope
in the entire loop.
You can declare a local variable with the same name in different blocks in a method, but
you cannot declare a local variable twice in the same block or in nested blocks, as shown in
Figure 5.6.
 
 
 
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