Java Programming Itis 1213 Gaddis Test 3

Front 1

The variable names references an integer array with 20 elements. Write a for loop that prints each element of the array.

Back 1

for( int i = 0; i < 20; i++)
System.out.println(names[i]);

Front 2

The variables numberArrayl and numberArray2 reference arrays that each have elements. Write code that copies the values in numberArrayl to numberArray2.

Back 2

for( int i = 0; i < numberArray2.length; i++)
numberArray2[i] = numberArray1[i];

Front 3

I. Write a statement that declares a String array initialized with the following string:
"Einstein", "Newton", "Copernicus", and "Kepler".

II. Write a loop that displays the contents of each element in the array you declared in Part a.

III. Write code that displays the total length of all the strings in the array you declared in Part a.

Back 3

String [ ] names = {"Einstein", "Newton", "Copernicus", "Kepler"};


for( int i = 0; i < 4; i++)
System.out.println(names[i]);

int intTotal = 0;
for( int i = 0; i < 4; i++)
intTotal = intTotal + names[i].length();
System.out.println(intTotal);

Front 4

I. In a program you need to store the populations of 12 countries.
a. Define two arrays that may be used in parallel to store the names of the countries and their populations.

b. Write a loop that uses these arrays to print each country's name and its population.

Back 4

a. String [ ] names = new String[12];
int [ ] pop = new int[12];

b. for( int i = 0; i < 12; i++)
System.out.println(names[i] + “ “ + pop[i]);

Front 5

In a program you need to store the identification numbers of 10 employees (as integers) and their weekly gross pay (as double values).

a. Define two arrays that may be used in parallel to store the 10 employee’s identification numbers and gross pay amounts.

b. Write a loop that uses these arrays to print each of the employees' identification number and weekly gross pay.

Back 5

a. int [ ] id = new int[10];
double [ ] pay = new double[10];

b. for( int i = 0; i < 10; i++)
System.out.println(id[i] + “ “ + pay[i]);

Front 6

a. Declare and create a two-dimensional int array named grades. It should have 30 rows and 10 columns.

b. Write code that calculates the average of all the elements in the grades array that you declared in a.

Back 6

a. int [ ] [ ] grades = new int [30] [10];

b. double totalGrades = 0;
int totalStudents = 0;
for( int i = 0; i < 30; i++)
for( int j = 0; j < 10; j++)
{
totalGrades = totalGrades + grades [i] [j];
totalStudents = totalStudents + 1;
}
System.out.println(totalGrades/totalStudents);

Front 7

Look at the following array declaration:
int [ ] [ ] numberArray = new int [9] [11];

a. Write a statement that assigns 145 to the first column of the first row of this array.


b. Write a statement that assigns 18 to the last column of the last row of this array.

Back 7

a. numberArray [0] [0] = 145;


b. numberArray [8] [10] = 18;

Front 8

The values variable references a two-dimensional double array with 10 rows and 20 columns. Write code that sums all the elements in the array and stores the sum in the variable total.

Back 8

double total = 0;
for( int i = 0; i < 10; i++)
for( int j = 0; j < 20; j++)
total = total + values [i] [j];

Front 9

An application uses a two-dimensional array declared as follows:
int [ ] [ ] days = new int [29] [5];

a. Write code that sums each row in the array and displays the results.


b. Write code that sums each column in the array and displays the results.

Back 9

a. int totalRow = 0;
for( int col = 0; col < 5; col++)
{
totalRow = 0;
for( int row = 0; row < 29; row++)
totalRow = totalRow + days [row][col];
System.out.println(totalRow);
}

b. int totalCol;
for( int row = 0; row < 29; row++)
{
totalCol = 0;
for( int col = 0; col < 5; col++)
totalCol = totalCol + days [row] [col];
System.out.println(totalCol);
}

Front 10

In an inheritance relationship, what is the general class called?

Back 10

superclass

Front 11

In an inheritance relationship, what is the specialized class called?

Back 11

subclass

Front 12

This key word indicates that a class inherits ftom another class.

Back 12

extends

Front 13

A subclass does not have access to these superclass members.

Back 13

private

Front 14

This key word refers to an object's superclass.

Back 14

super

Front 15

In a subclass constructor, a call to the superclass constructor must appear where?

Back 15

first statement

Front 16

What is method overriding?

Back 16

method in subclass has the same signature as method in superclass.

Front 17

Write the first line of the definition for a Poodle class. The class should inherit from the Dog class.

Back 17

public class Poodle extends Dog

Front 18

Look at the following code which is the first line of a class definition:
public class Bear extends Animal
In what order will the class constructors execute?

Back 18

Animal, then Bear

Front 19

Write the statement that calls a superclass constructor and passes the arguments x, y, and z.

Back 19

super(x, y, z);

Front 20

A superclass has the following method:
public void setNumber (int n)
{
number = n;
}

Write a statement that can appear in a subclass that calls this method, passing 25 as an argument.

Back 20

setNumber(25);

Front 21

Write the first line of the definition for a Stereo class. The class should inherit from the SoundSystem class and should implement the CDPlayable interface.

Back 21

public class Stereo extends SoundSystem implements CDPlayable

Front 22

Write an interface named Nameable that specifies the following methods:
public void setName (String n)
public String getName ()

Back 22

public interface Nameable
{
void setName(String n);
String getName();
}

Front 23

The following if statement determines whether choice is equal to „Y‟ or „y‟
if(choice == „Y‟ || choice == „y‟)
Rewrite this statement so it only makes one comparison and does not use the || operator . (Hint: Use either the toUpperCase or toLowerCase methods.)

2. Write a loop that counts the number of space characters that appear in the String object line

Back 23

if (Character.toUpperCase(choice) == ‘Y’)

String line;
int totalSpace = 0;
for (int i = 0; i < line.length(); i++)
{
if (Character.isSpaceChar(line.charAt(i))) totalSpace ++;
}

Front 24

a. Write a loop that counts the number of space characters that appear in the String object line.

b. Shorter version

Back 24

a. String line;
char ch;
int totalSpace = 0;
for (int i = 0; i < line.length(); i++)
{
ch = line.charAt(i);
if (Character.isSpaceChar(ch)) totalSpace ++;
}


b. String line;
int totalSpace = 0;
for (int i = 0; i < line.length(); i++)
{
if (Character.isSpaceChar(line.charAt(i)))
totalSpace++;
}

Front 25

Write a loop that counts the number of digits that appear in the String object line.

Back 25

String line;
int totalDigit = 0;
for (int i = 0; i < line.length(); i++)
{
if (Character.isDigit(line.charAt(i))) totalDigit ++;
}

Front 26

Write a loop that counts the number of lowercase characters that appear in the String object line.

Back 26

int totalLower = 0;
for (int i = 0; i < line.length(); i++)
{
if (Character.isLowerCase(line.charAt(i))) totalLower ++;
}

Front 27

Look at the following string:
“cookies>milk>fudge:cake:ice cream”

Write code using a StringTokenizer object that extracts the following tokens from the string and displays them: cookies, milk, fudge, cake, and ice cream.

Back 27

StringTokenizer token = new StringTokenizer (“cookies>milk>fudge:cake:ice cream”, “>:”);
while (token.hasMoreTokens())
System.out.println (token.nextToken());

Front 28

Assume that d is a double variable. Write an if statement that assigns d to the int variable i, if the value in d is not larger than the maximum value for an int.

Back 28

if ((int) d <= Integer.MAX_VALUE)
i = (int) d;

Front 29

______ variables are designed to hold only one value at a time.

Back 29

Primitive

Front 30

Arrays allow us to create a collection of like values that are _______.

Back 30

indexed

Front 31

An array can store any ________ but only one type of data at a time

Back 31

type of data

Front 32

An array is a list of _______.

Back 32

data elements

Front 33

An array is an object so it needs an ________.

Back 33

object reference

int[] numbers;

Front 34

The array size must be a ____ number.

Back 34

non-negative

Front 35

An array is accessed by:

Back 35

the reference name
a subscript that identifies which element in the array to access.

Front 36

The length of an array can be obtained via its ____ constant

Back 36

length

ex: int size = temperatures.length;

Front 37

It is possible to get the size of an array from a user:

Back 37

String input;
int numTests;
int[] tests;
input =
JOptionPane.showInputDialog(null, "How many numbers do you have? ");
numTests = Integer.parseInt(input);
tests = new int[numTests];

Front 38

Finding the Highest Value:

Back 38

int [] numbers = new int[50];
int highest = numbers[0];
for (int i = 1; i < numbers.length; i++)
{
if (numbers[i] > highest)
highest = numbers[i];
}

Front 39

Finding the Lowest Value:

Back 39

int lowest = numbers[0];
for (int i = 1; i < numbers.length; i++)
{
if (numbers[i] < lowest)
lowest = numbers[i];
}

Front 40

Summing Array Elements:

Back 40

int total = 0; // Initialize accumulator
for (int i = 0; i < units.length; i++)
total += units[i];

Front 41

Averaging Array Elements:

Back 41

double total = 0; // Initialize accumulator
double average; // Will hold the average
for (int i = 0; i < scores.length; i++)
total += scores[i];
average = total / scores.length;

Front 42

To use the class, the import statement:

Back 42

import java.util.Array;

Front 43

The return type of the method must be declared as an array of the right type.

Back 43

public static double[] getArray()
{
double[] array = { 1.2, 2.3, 4.5, 6.7, 8.9 };
return array;
}

Front 44

Arrays have a final field named ______.

Back 44

length

Front 45

String objects have a method named ______.

Back 45

length

Front 46

An array’s length is a field

Back 46

You do not write a set of parentheses after its name.

Front 47

A String’s length is a method

Back 47

You do write the parentheses after the name of the String class’s length method.

Front 48

By using the same subscript, you can build relationships between data stored in two or more arrays:

Back 48

String[] names = new String[5];
String[] addresses = new String[5];

Front 49

An ______ is an object that describes an unusual or erroneous situation

Back 49

exception

Front 50

Exceptions are thrown by a program, and may be _____ and _______ by another part of the program

Back 50

caught
handled

Front 51

A program can be separated into a _____ execution flow and an _______ execution flow

Back 51

normal
exception

Front 52

Java has a ______ set of exceptions and errors that can occur during execution

Back 52

predefined

Front 53

VERY IMPORTANT!!!!!!!!!!

The relationship between a superclass and an inherited class is called an _______.

Back 53

“is a” relationship

Front 54

We can _______ the capabilities of a class

Back 54

extend

Front 55

Inheritance involves a _______ and a subclass

Back 55

superclass

Front 56

The subclass is based on, or _______ from, the superclass.

Back 56

extended

Front 57

The relationship of classes can be thought of as parent ______ and _________.

Back 57

classes and child classes

Front 58

The subclass inherits fields and methods from the superclass without any of them being _______.

Back 58

rewritten

Front 59

The Java keyword, _______, is used on the class header to define the subclass.

Back 59

extends

ex: public class FinalExam extends GradedActivity

Front 60

Members of the superclass that are marked _____

-are not inherited by the subclass

Back 60

private

Front 61

Members of the superclass that are marked _______.

-are inherited by the subclass

Back 61

public

Front 62

Constructors are ________.

Back 62

not inherited

Front 63

When a subclass is instantiated, the _______ _______ constructor is executed first.

Back 63

superclass default

Front 64

The _______ keyword refers to an object’s superclass.

Back 64

super

Front 65

The subclass method overrides the superclass method.
This is known as _________.

Back 65

method overriding

Front 66

The class StringTokenizer is in the _____ package.

Back 66

java.util

Front 67

the constructor method:

Back 67

public StringTokenizer (String theString)

StringTokenizer tokens = new StringTokenizer(line)

Front 68

Constructor for a tokenizer that will use the characters in the string delimiters as separators when finding tokens in theString:

Back 68

StringTokenizer tokens = new StringTokenizer(line, “,-”)

Front 69

Returns true if there are more tokens in theString; returns false otherwise.

Back 69

public boolean hasMoreTokens()

Front 70

Returns the next token from theString

Back 70

public String nextToken()

Front 71

Returns the number of tokens remaining to be returned by nextToken

Back 71

public int countTokens()

Front 72

In each of the following statements us in the StringTokenizer class, how many tokens would be returned?
String line = “Ed’s ID# is 234-61-9876!”;
a. StringToken tokens = new StringTokenizer(line, “-”)
b. StringToken tokens = new StringTokenizer(line, “#-”)
c. StringToken tokens = new StringTokenizer(line, “#’-”)

Back 72

a. 3

b. 4

c. 5

Front 73

An _______ is an object that describes an unusual or erroneous situation

Back 73

exception

Front 74

Exceptions are thrown by a program, and may be caught and handled by _________.

Back 74

another part of the program

Front 75

A program can be separated into a normal execution flow and an _______ execution flow

Back 75

exception

Front 76

If an exception is ignored by the program, the program will ___________ and produce an appropriate message

Back 76

terminate abnormally

Front 77

To process an exception when it occurs, the line that throws the exception is executed within a _______.

Back 77

try block

Front 78

A ______ is followed by one or more catch clauses, which contain code to process an exception

Back 78

try block

Front 79

Each catch clause has an associated exception type and is called an _________

Back 79

exception handler

Front 80

A try statement can have an optional clause following the catch clauses, designated by the reserved word _______

Back 80

finally

Front 81

The statements in the finally clause _____ are executed

Back 81

always

Front 82

When working with GUI, the two sets classes that we focus on are ______ classes

Back 82

AWT and Swing

Front 83

AWT is ___________.

Back 83

the Abstract Windowing Toolkit (AWT)

Front 84

Swing is a library of classes that provide an __________.

Back 84

improved alternative for creating GUI applications and applets

Front 85

The Swing classes are part of the _______ package.

Back 85

javax.swing

Front 86

In the main method, two constants are declared to set the window size:

Back 86

final int WINDOW_WIDTH = 350,
WINDOW_HEIGHT = 250;