Java Reference
In-Depth Information
Table 7.1 Zero-Equivalent
Auto-Initialization Values
Type
Value
int
0
double
0.0
char
'\0'
boolean
false
objects
null
to the array (
temperature
) with a specific index (
[0]
,
[1]
, or
[2]
). So, there is an
element known as
temperature[0]
, an element known as
temperature[1]
, and an
element known as
temperature[2]
.
In the
temperature
array diagram, each of the array elements has the value
0.0
.
This is a guaranteed outcome when an array is constructed. Each element is initialized
to a default value, a process known as
auto-initialization.
Auto-Initialization
The initialization of variables to a default value, such as on an array's ele-
ments when it is constructed.
When Java performs auto-initialization, it always initializes to the zero-equivalent
for the type. Table 7.1 indicates the zero-equivalent values for various types. The special
value
null
will be explained later in this chapter.
Notice that the zero-equivalent for type
double
is
0.0
, which is why the array ele-
ments were initialized to that value. Using the indexes, you can store the specific
temperature values that are relevant to this problem:
temperature[0] = 74.3;
temperature[1] = 68.4;
temperature[2] = 70.3;
This code modifies the array to have the following values:
[0]
[1]
[2]
temperature
74.3
3
68.4
3
70.3
3
Obviously an array isn't particularly helpful when you have just three values to
store, but you can request a much larger array. For example, you could request an
array of 100 temperatures by writing the following line of code:
double[] temperature = new double[100];
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