Java Reference
In-Depth Information
46 }
47
48 System.out.println(
"Your birthday is "
+ day);
49 }
50 }
A three-dimensional array
dates
is created in Lines 8-28. This array stores five sets of
numbers. Each set is a 4-by-4 two-dimensional array.
The loop starting from line 33 displays the numbers in each set and prompts the user to
answer whether the birthday is in the set (lines 41-42). If the day is in the set, the first number
(
dates[i][0][0]
) in the set is added to variable
day
(line 45).
8.8
✓
✓
Declare an array variable for a three-dimensional array, create a 4
*
6
*
5
int
Check
array, and assign its reference to the variable.
Point
8.9
Assume
int[][][] x = new char[12][5][2]
, how many elements are in the
array? What are
x.length
,
x[2].length
, and
x[0][0].length
?
8.10
Show the output of the following code:
int
[][][] array = {{{
1
,
2
}, {
3
,
4
}}, {{
5
,
6
},{
7
,
8
}}};
System.out.println(array[
0
][
0
][
0
]);
System.out.println(array[
1
][
1
][
1
]);
C
HAPTER
S
UMMARY
1.
A two-dimensional array can be used to store a table.
2.
A variable for two-dimensional arrays can be declared using the syntax:
elementType[][] arrayVar
.
3.
A two-dimensional array can be created using the syntax:
new elementType
[ROW_SIZE][COLUMN_SIZE]
.
4.
Each element in a two-dimensional array is represented using the syntax:
arrayVar[rowIndex][columnIndex]
.
5.
You can create and initialize a two-dimensional array using an array initializer with the
syntax:
elementType[][] arrayVar = {{row values}, . . . , {row values}}
.
6.
You can use arrays of arrays to form multidimensional arrays. For example, a variable
for three-dimensional arrays can be declared as
elementType[][][] arrayVar
, and
a three-dimensional array can be created using
new elementType[size1][size2]
[size3]
.
Q
UIZ
P
ROGRAMMING
E
XERCISES
*8.1
(
Sum elements column by column
) Write a method that returns the sum of all the
elements in a specified column in a matrix using the following header:
public static double
sumColumn(
double
[][] m,
int
columnIndex)
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