Question 1

Where is the error in the following code sequence, and why? How would you correct it?
int number = 6;
double d = number;
number = 19.0;

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Question 2

Convert the String input below to an int and display 4 times that value. Do not hard code either 7 or 28; assume that you do not know the value of input.
String input = "7";

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Question 3

Complete the code, drawing a solid circle (with the current fill color, whatever it is) so that its diameter is 200 and the coordinates of its center are (250, 150).
// gc is a GraphicsContext reference
// your code goes here

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Question 4

Assuming a is an int variable and flag is a boolean variable, apply one of DeMorgan's laws to create an equivalent expression for the following boolean expression:
!( a == 100 || flag == false )

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Question 5

A String variable named s has been declared and holds some value. If its number of characters is even, output EVEN; otherwise, output ODD.

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Question 6

Inside the main method, prompt the user to enter a word that does not contain a Y until the user enters one.

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Question 7

Write a loop to output the word "FINAL" 25 times.

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Question 8

Consider the following class:
public class Radio
{
private double frequency;
private String name;
// overloaded constructor
// accessors (get methods)
// mutators (set methods)
// other methods
}
Code the two mutators. Frequency must be between 80 and 110 included. If the parameter is out of that range, set the frequency to 100. There is no constraint on name. The mutators should return the Radio reference that calls them.
// Your code goes here

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public class Radio
{
private double...

Question 9

Consider the following class:
public class Radio
{
private double frequency;
private String name;
// overloaded constructor
// accessors (get methods)
// mutators (set methods)
// other methods
}
Code the overloaded constructor. Call the mutators (set methods) to enforce constraints. Assume that they have been coded correctly.
// Your code goes here

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public class Radio
{
private double...

Question 10

Write the code to compute and output how many times the value 99 is found in an array of integers named numbers.

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Question 11

An array, numbers, has been declared and initialized as follows:
int [ ] numbers = { 45, 78, 99, 12, 66 };
What is the index of 78?
What is the array element at index 4?
Change the array so that we have value 77 instead of 99.
Swap the value at indexes 1 and 2 without knowing what the values are.
Using a loop, assume that you do not know how many elements are in the array and increase all the values of numbers by 10.
Using a loop, assume that you do not know how many elements are in the array and what they are, and calculate and output the number of elements that are strictly greater than 50.
Using a loop, assume that you do not know how many elements are in the array and output every other element of the array, starting at the first element.

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Question 12

An array, letters, has been declared and initialized as follows:
char [ ] letters = { 'A', 'B', 'A', 'C', 'E', 'D' };
What is the index of C?
What is the array element at index 1?
Swap the value at indexes 3 and 5 (C and D) without knowing what the values are. After the swap, the array will look like A B A D E C.
Using a loop, assume that you do not know how many elements are in the array and the contents of the array, and compute and output how many As are in the array letters.
Using a loop, assume that you do not know how many elements are in the array and the contents of the array, and change all the As of letters into Zs; do not change the other letters.

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Question 13

Code a method that returns an int array that is parallel to its array parameter letters. If an element of letters is A, the corresponding element of the returned array is 1; otherwise, it is 0.
Example 1: If the array parameter is A B A, the returned array is 1 0 1.
Example 2: If the array parameter is A B A C D A A, the returned array is 1 0 1 0 0 1 1.
Example 3: If the array parameter is A A E F G, the returned array is 1 1 0 0 0.
public static int [ ] convert( char [ ] letters )
{
// Your code goes here
}

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Question 14

Here is the code for selection sort (for an array of ints):
public static void selectionSort( int [ ] arr )
{
int temp;
int max;
for ( int i = 0; i < arr.length - 1; i++ )
{
max = indexOfLargestElement( arr, arr.length - i );
System.out.println( "max = " + max );
temp = arr[max];
arr[max] = arr[arr.length - i - 1];
arr[arr.length - i - 1] = temp;
}
}
public static int indexOfLargestElement( int [ ] arr, int size )
{
int index = 0;
for ( int i = 1; i < size; i++ )
{
if ( arr[i] > arr[index] )
index = i;
}
return index;
}
We are running the following code:
int [ ] numbers = { 10, 6, 4, 8 };
selectionSort( numbers );
Show what the output statement in the selectionSort method outputs. The question is not what the array looks like at the end; we know it is sorted in ascending order.

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Question 15

Consider the following two-dimensional array:
String [ ][ ] states = { { "CA", "CO" },
{ "MD", "IL", "ME", "MI" }, { "NY", "NJ", "NE" } };
What is the value of states[2][1]?
Retrieve ME from the array states and assign it to a String variable of your choice.
Using a loop, output all the states that start with the letter M in the second row (as in this example).
Assume that you do not know how many columns are in the second row, i.e., do not hard code 4. Assume that you do not know that the three states are MD, ME, and MI.

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String [ ][...

Question 16

The variable cities is an ArrayList of type String, Write the code to output all its elements.

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Question 17

The variable numbers is a two-dimensional array of type int. Output all of its elements that are strictly greater than 10.

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Question 18

The ArrayList method trimToSize has the following API: public void trimToSize( ) It trims the capacity of this ArrayList instance to be the list's current size. ArrayList numbers = new ArrayList( ); numbers.add( 32 ); numbers.add( 17 ); numbers.add( 6 ); Use trimToSize to trim the capacity of numbers to its current size:

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Question 19

The ArrayList method indexOf has the following API: public int indexOf( HYPERLINK "http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html" \o "class in java.lang" Object o) Return the index of the first occurrence of o in this list or -1 if this list does not contain o. ArrayList cities = new ArrayList( ); cities.add( "Baltimore" ); // more statements adding cities to the ArrayList cities Use indexOf to retrieve the index of the city New York in cities (it may or may not be there) and assign the result to a variable of your choice.

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Question 20

Class Reply inherits from class Post. Write the header for class Reply (one line only).

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Quiz 16: RGB Colors, Decimal Conversion, Java Naming, and Random Number Generation

Where is the error in the following code sequence, and why? How would you correct it? int number = 6; double d = number; number = 19.0;

Convert the String input below to an int and display 4 times that value. Do not hard code either 7 or 28; assume that you do not know the value of input. String input = "7";

Complete the code, drawing a solid circle (with the current fill color, whatever it is) so that its diameter is 200 and the coordinates of its center are (250, 150). // gc is a GraphicsContext reference // your code goes here

Assuming a is an int variable and flag is a boolean variable, apply one of DeMorgan's laws to create an equivalent expression for the following boolean expression: !( a == 100 || flag == false )