Output of Java Programs | Set 42 (Arrays)
Prerequisite : Java Arrays
Question 1. What is the output of this question?
class Test1 { public static void main(String[] args) { int arr[] = new int [ 5 ]; int arr2[] = new int [ 'a' ]; byte bt = 10 ; int arr3[] = new int [bt]; System.out.println(arr.length); System.out.println(arr2.length); System.out.println(arr3.length); } } |
Option
A) Error
B) Runtime Exception
C) 5
97
10
D) 5
65
10
Output: C
Explanation : To specify array size allowed data type are – byte, short, int, char and all of these are valid data types here.
Question 2. What is the output of this question?
class Test2 { public static void main(String[] args) { int a[] = new int [ 5 ]; // line 1 int [] a11 = new int []; // line 2 } } |
Option
A) Error
B) Exception
C) Run successfully
D) None
Output: A
Explanation : One Dimension array have size declaration as compulsory feature.
Error : array dimension missing int []a11 = new int[]; // line 2
Question 3. Which of the following declarations are invalid?
class Test3 { public static void main(String[] args) { int [][] arr1 = new int [ 2 ][ 3 ]; // Line 1 int [][] arr2 = new int [ 2 ][]; // line 2 int [][] arr3 = new int [][]; // line 3 int [][] arr4 = new int [][ 2 ]; // line 4 } } |
Option
A) All
B) line 1, 3, 4
C) line 3, 4
D) line 2, 3, 4
Output: C
Explanation : First two declarations are allowed and so no error. line 3 and 4 have zero and last dimension respectively.
error: array dimension missing
int [][]arr3=new int[][];//line 3 ^ error: ']' expected int [][]arr4=new int[][2];//line 4 ^ error: ';' expected int [][]arr4=new int[][2];//line 4
Question 4. Which of the following lines give error?
class Test4 { public static void main(String[] args) { int [][][] arr1 = new int [ 1 ][ 2 ][ 3 ]; // Line 1 int [][][] arr2 = new int [ 1 ][ 2 ][]; // Line 2 int [][][] arr3 = new int [ 2 ][][]; // Line 3 int [][][] arr4 = new int [][][]; // Line 4 int [][][] arr5 = new int [][ 2 ][ 3 ]; // Line 5 int [][][] arr6 = new int [][][ 3 ]; // Line 6 int [][][] arr7 = new int [][ 2 ][]; // Line 7 } } |
Option
A) line 4, 5, 6, 7
B) All
C) No Error
D) line 4, 7
Output: A
Explanation : In three dimensional array have first two dimension declaration is compulsory other wise we will get compile time error:illegal startup expression.
Question 5. What is the output of this question?
class Test5 { public static void main(String[] args) { int arr[] = new int [ 5 ]; System.out.println(arr); System.out.println(arr[ 0 ]); } } |
Option
A) 0
0
B)[I@6bc7c054
0
C) 0 0 0 0 0
0
D) none
Output: B
Explanation : arr : It is giving the base address of array
arr[0] : It is giving value of array element at 0th location.
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