Question 1

Suppose you wish to write a method that returns the sum of the elements in the partially filled array myArray. Which is a reasonable method header?

Accepted Answer

A)   public static int sum(int[] values) 
B)   public static int sum() 
C)   public static int sum(int[] values, int currSize) 
D)   public static int sum(int[] values, int size, int currSize)  C

Question 2

What is the output of the given code snippet?
Int[] mynum = new int[5];
For (int i = 1; i < 5; i++)
{
Mynum[i] = i + 1;
System.out.print(mynum[i]);
}

Accepted Answer

A)   2345
B)   1234
C)   1345
D)   1111 A

Question 3

The following statement gets an element from position 4 in an array: x = a[4];
What is the equivalent operation using an array list?

Accepted Answer

A)   x = a.get(4) ;
B)   x = a.get() ;
C)   x = a.get[4];
D)   x = a[4]; A

Question 4

Identify the correct statement for defining an integer array named numarray of ten elements.

Accepted Answer

A)   int[] numarray = new int[9];
B)   int[] numarray = new int[10];
C)   int[10] numarray;
D)   int numarray[10];

Question 5

Consider the following code snippet: public static void check(ArrayList<Integer> chknum1)
{
Int cnt = 0;
For(int i = 0; i < chknum1.size(); i++)
{
If(chknum1.get(i) == 0)
{
Cnt++;
}
}
System.out.println("The total 0 values in the list are: " + cnt);
}
Which one of the following is true about the check method in the given code snippet?

Accepted Answer

A)   The check method counts all the elements with value 0 in an array list passed as a parameter to the method.
B)   The check method removes all the elements with value 0 from an array list passed as a parameter to the method.
C)   The check method counts all the elements with value 0 in an array list passed as a parameter to a method and also returns the count.
D)   The check method adds 0 to the elements of an array list as a parameter to a method and also returns the array list.

Question 6

What is the output of the following code snippet? public static int check(ArrayList listData) { Int sum = 0; For (int i = 0; i < listData.size(); i++) { Sum = sum + listData.get(i); } Return sum; } Public static void main(String[] args) { ArrayList vdata = new ArrayList(); Int rsum; For (int cnt = 0; cnt < 3; cnt++) { Vdata.add(cnt + 1); } Rsum = check(vdata); System.out.println(rsum); }

Accepted Answer

A)   4
B)   2
C)   3
D)   6

Question 7

The enhanced for loop

Accepted Answer

A)   is convenient for traversing all elements in an array
B)   is convenient for traversing elements in a partially filled array
C)   is only used for arrays of integers
D)   is used to initialize all array elements to a common value

Question 8

Consider the telephone book as a physical object that can help understand algorithms. What kind of algorithm might be visualized using it?

Accepted Answer

A)   Sorting
B)   Searching
C)   Finding the maximum
D)   Monte Carlo methods

Question 9

Which one of the following is a valid signature of a method with an integer two-dimensional array parameter of size 10 x 10?

Accepted Answer

A)   public static void func(int[][] arr) 
B)   public static void func(int[10][] arr) 
C)   public static void func(int[][10] arr) 
D)   public static void func(int[10][10] arr)

Question 10

Which one of the following statements is correct for the given code snippet?
Int[] number = new int[3]; // Line 1
Number[3] = 5; // Line 2

Accepted Answer

A)   Line 2 declares and initializes an array of three elements with value 5.
B)   Line 2 causes a bounds error because 3 is an invalid index number.
C)   Line 2 initializes the third element of the array with value 5.
D)   Line 2 initializes all the elements of the array with value 5.

Question 11

The integer array numbers will be filled with the values from the Scanner in. If there are more input values than there are spaces in the array, only enough values to fill the array should be read. The integer variable currentSize should be set to the number of values read. Partial code to do this is given below:
Int[] numbers; // Assume it is created with at least 1 space
Scanner in = new Scanner (System.in);
Int currentSize = 0;
While (/* Put condition here */)
{
Int value = in.nextInt();
Numbers[currentSize] = value;
CurrentSize++;
}
What condition will complete this code?

Accepted Answer

A)  currentSize 
B)  currentSize 
C)  currentSize 
D)  currentSize <= numbers.length || in.hasNextInt()

Question 12

Which one of the following statements is true about passing arrays to a method?

Accepted Answer

A)   By default, arrays are passed by value to a method
B)   Arrays, when updated in a called method, are not reflected to the calling method
C)   By default, arrays are passed by reference to a method
D)   Arrays are passed only if size is specified as another argument

Question 13

What will be printed by the statements below?
Int[] values = { 4, 5, 6, 7};
For (int i = 1; i < values.length; i++)
Values[i] = values[i - 1] + values[i];
For (int i = 0; i < values.length; i++)
System.out.print (values[i] + " ");

Accepted Answer

A)  4 9 11 13
B)  4 9 15 22
C)  9 11 13 7
D)  4 5 6 7

Question 14

Assume the array of integers values has been created. Which condition must be used in the indicated area so the loop below will assign max the largest value in values?
Int max = values[0];
For (int val: values)
{
If (/* Put condition here */)
Max = val;
}

Accepted Answer

A)  max > val
B)  val > max
C)  values[val] > max
D)  max > values[val]

Question 15

What is the result of the following definition of an array list? ArrayList<Double> points;

Accepted Answer

A)   The statement causes a compile time error as the size of the array list is not defined.
B)   The statement creates an array list of size 0.
C)   The statement creates an array list with unlimited size.
D)   The statement defines an array list reference but does not create an array list.

Question 16

Suppose you wish to use an array to solve a new problem. What is the first step to take in finding a solution?

Accepted Answer

A)   structure a program using methods
B)   adapt a built-in array algorithm
C)   decompose the problem into steps
D)   assemble a test program and run it

Question 17

What is the output of the following statements? ArrayList cityList = new ArrayList(); CityList.add("London"); CityList.add("New York"); CityList.add("Paris"); CityList.add("Toronto"); CityList.add("Hong Kong"); CityList.add("Singapore"); System.out.print(cityList.size()); System.out.print(" " + cityList.contains("Toronto")); System.out.print(" " + cityList.indexOf("New York")); System.out.println(" " + cityList.isEmpty());

Accepted Answer

A)   5 true 1 false
B)   6 true 2 false
C)   5 false 1 false
D)   6 true 1 false

Question 18

Consider the following code snippet. Which statement should be used to fill in the empty line so that the output will be [32, 54, 67.5, 29, 35]? public static void main(String[] args)
{
Double data[] = {32, 54, 67.5, 29, 35};
______________
System.out.println(str);
}

Accepted Answer

A)   String str = Arrays.format(data) ;
B)   String str = data.toString() ;
C)   String str = Arrays.toString(data) ;
D)   String str = str + ", " + data[i];

Question 19

What is the value of the cnt variable after the execution of the code snippet below? ArrayList somenum = new ArrayList(); Somenum.add(1); Somenum.add(2); Somenum.add(1); Int cnt = 0; For (int index = 0; index < somenum.size(); index++) { If (somenum.get(index) % 2 == 0) { Cnt++; } }

Accepted Answer

A)   1
B)   2
C)   3
D)   0

Question 20

Consider the following code snippet: ArrayList somedata = new ArrayList(); Somedata.add(10.5); What is the size of the array list somedata after the given code snippet is executed?

Accepted Answer

A)   0
B)   1
C)   10
D)   2

Exam 7: Arrays and Array Lists

Suppose you wish to write a method that returns the sum of the elements in the partially filled array myArray. Which is a reasonable method header?

What is the output of the given code snippet? Int[] mynum = new int[5]; For (int i = 1; i < 5; i++) { Mynum[i] = i + 1; System.out.print(mynum[i]) ; }

The following statement gets an element from position 4 in an array: x = a[4]; What is the equivalent operation using an array list?

Identify the correct statement for defining an integer array named numarray of ten elements.

The enhanced for loop

Consider the telephone book as a physical object that can help understand algorithms. What kind of algorithm might be visualized using it?

Which one of the following is a valid signature of a method with an integer two-dimensional array parameter of size 10 x 10?

Which one of the following statements is correct for the given code snippet? Int[] number = new int[3]; // Line 1 Number[3] = 5; // Line 2

Which one of the following statements is true about passing arrays to a method?

What will be printed by the statements below? Int[] values = { 4, 5, 6, 7}; For (int i = 1; i < values.length; i++) Values[i] = values[i - 1] + values[i]; For (int i = 0; i < values.length; i++) System.out.print (values[i] + " ") ;

Assume the array of integers values has been created. Which condition must be used in the indicated area so the loop below will assign max the largest value in values? Int max = values[0]; For (int val: values) { If (/* Put condition here */) Max = val; }

What is the result of the following definition of an array list? ArrayList<Double> points;

Suppose you wish to use an array to solve a new problem. What is the first step to take in finding a solution?

Consider the following code snippet. Which statement should be used to fill in the empty line so that the output will be [32, 54, 67.5, 29, 35]? public static void main(String[] args) { Double data[] = {32, 54, 67.5, 29, 35}; ______________ System.out.println(str) ; }

Consider the following code snippet: ArrayList<Double> somedata = new ArrayList<Double>() ; Somedata.add(10.5) ; What is the size of the array list somedata after the given code snippet is executed?