Deck 2: Data and Expressions

Question 1

If x is an int and y is a float, all of the following are legal except which assignment statement?

A) y = x;
B) x = y;
C) y = (float) x;
D) x = (int) y;
E) all of the above are legal

Answer 1

B
Explanation: B) Since x is an int, it cannot except a float unless the float is cast as an int. There is no explicit cast in the assignment statement in B. In A, a cast is not necessary because a float (y) can accept an int value (x), and in C and D, explicit casts are present making them legal.

Question 2

Which of the following is True regarding the mod operator, %?

A) It can only be performed on int values and its result is a double
B) It can only be performed on int values and its result is an int
C) It can only be performed on float or double values and its result is an int
D) It can only be performed on float or double values and its result is a double
E) It can be performed on any numeric values, and the result always is numeric

Answer 2

E
Explanation: E) Mod, or modulo, returns the remainder that results from a division. The remainder is always is numeric. Although usually integer values are used, the % operator may be used on all kinds of numeric data.

Question 3

Use the following class definition to answer the questions below.
public class Questions
{
public static void main(String[ ] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
A reasonable documentation comment for this program might be

A) // a program that demonstrates the differences between print, println and how + works
B) // a program that outputs a message about Texas
C) // a program that demonstrates nothing at all
D) // a program that outputs the message "Here There Everywhere But not in Texas"
E) // a program that contains three output statements

Answer 3

A
Explanation: A) Remember that comments should not state the obvious (ruling out D and E) but instead should explain what the program is doing or why. This program demonstrates print and println and +.

Question 4

The word println is a(n)

A) method
B) reserved word
C) variable
D) class
E) String

Question 5

Given the following assignment statement, which of the following answers is True regarding the order that the operators will be applied based on operator precedence?
A = (b + c) * d / e - f;

A) *, /, +, -
B) *, +, /, -
C) +, *, /, -
D) +, /, *, -
E) +, -, *, /

Question 6

What is output with the statement System.out.println(x+y); if x and y are int values where x=10 and y=5?

A) 15
B) 105
C) 10 5
D) x+y
E) An error since neither x nor y is a String

Question 7

Use the following class definition to answer the questions below.
public class Questions
{
public static void main(String[ ] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
The program will print the word "Here" and then print

A) "There Everywhere" on the line after "Here"
B) "There" on the line after "Here" and "Everywhere" on the line after "There"
C) "There Everywhere" on the same line as "Here"
D) "ThereEverywhere" on the same line as "Here"
E) "ThereEverywhere" on the line after "Here"

Question 8

If you want to output the text "hi there", including the quote marks, which of the following could do that?

A) System.out.println("hi there");
B) System.out.println(""hi there"");
C) System.out.println("\"hi there");
D) System.out.println("\"hi there\"");
E) none, it is not possible to output a quote mark because it is used to mark the beginning and ending of the String to be output

Question 9

A Java variable is the name of a

A) numeric data value stored in memory
B) data value stored in memory that can not change during the program's execution
C) data value stored in memory that can change its value but cannot change its type during the program's execution
D) data value stored in memory that can change both its value and its type during the program's execution
E) data value or a class stored in memory that can change both its value and its type during the program's execution

Question 10

Assume that x, y, and z are all integers (int) equal to 50, 20, and 6 respectively. What is the result of x / y / z?

A) 0
B) 12
C) 16
D) A syntax error as this is syntactically invalid
E) A run-time error because this is a division by 0

Question 11

A cast is required in which of the following situations?

A) using charAt to take an element of a String and store it in a char
B) storing an int in a float
C) storing a float in a double
D) storing a float in an int
E) all of the above require casts

Question 12

Of the following types, which one cannot store a numeric value?

A) int
B) byte
C) float
D) char
E) all of these can store numeric values

Question 13

Use the following class definition to answer the questions below.
public class Questions
{
public static void main(String[ ] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
How many lines of output are provided by this program?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 14

Use the following class definition to answer the questions below.
public class Questions
{
public static void main(String[ ] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
The final println command will output

A) "But not in Texas"
B) "But notin Texas"
C) "But not" on one line and "in Texas" on the next line
D) "But not+in Texas"
E) "But not + in Texas"

Question 15

If you want to store into the String name the value "George Bush", you would do which statement?

A) String name = "George Bush";
B) String name = new String("George Bush");
C) String name = "George" + " " + "Bush";
D) String name = new String("George" + " " + "Bush");
E) Any of the above would work

Question 16

What is output with the statement System.out.println(""+x+y); if x and y are int values where x=10 and y=5?

A) 15
B) 105
C) 10 5
D) x+y
E) An error since neither x nor y is a String

Question 17

What will be the result of the following assignment statement? Assume b = 5 and c = 10.
Int a = b * (-c + 2) / 2;

A) 30
B) -30
C) 20
D) -20
E) -6

Question 18

What value will z have if we execute the following assignment statement?
Float z = 5 / 10;

A) z will equal 0.0
B) z will equal 0.5
C) z will equal 5.0
D) z will equal 0.05
E) none of the above, a run-time error arises because z is a float and 5 / 10 is an int

Question 19

Consider the following statement: System.out.println("1 big bad wolf\t8 the 3 little pigs\n4 dinner\r2night");
This statement will output ________ lines of text

A) 1
B) 2
C) 3
D) 4
E) 5

Question 20

Consider having three String variables a, b, and c. The statement c = a + b; also can be achieved by saying

A) c = a.length( ) + b.length( );
B) c = (int) a + (int) b;
C) c = a.concat(b);
D) c = b.concat(a);
E) c = a.plus(b);

Question 21

Assume that x is a double that stores 0.362491. To output this value as 36%, you could use the NumberFormat class with NumberFormat nf = NumberFormat.getPercentInstance( ); Which of the following statements then would output x as 36%?

A) System.out.println(x);
B) System.out.println(nf);
C) System.out.println(nf.x);
D) System.out.println(nf.format(x));
E) System.out.println(format(x));

Question 22

Which library package would you import to use the class Random?

A) java.beans
B) java.io
C) java.lang
D) java.text
E) java.util

Question 23

Which of the following would return the last character of the String x?

A) x.charAt(0);
B) x.charAt(last);
C) x.charAt(length(x));
D) x.charAt(x.length( )-1);
E) x.charAt(x.length( ));

Question 24

For the following questions, refer to the class defined below:
import java.util.Scanner;
public class Questions
{
public static void main(String[ ] args)
{
int x, y, z;
double average;
Scanner scan = new Scanner(System.in);
System.out.println("Enter an integer value");
x = scan.nextInt( );
System.out.println("Enter another integer value");
y = scan.nextInt( );
System.out.println("Enter a third integer value");
z = scan.nextInt( );
average = (x + y + z) / 3;
System.out.println("The result of my calculation is " + average);
}
}
What is output if x = 0, y = 1 and z = 1?

A) 0
B) 0.0
C) 0.6666666666666666
D) 0.6666666666666667
E) 0.67

Question 25

Consider the following paint method and answer the questions below:
public void paint(Graphics page)
{
page.setColor(Color.blue);
page.fillRect(50, 50, 100, 100);
page.setColor(Color.white);
page.drawLine(50, 50, 150, 150);
page.drawLine(50, 150, 150, 50);
page.setColor(Color.black);
page.drawString("A nice box", 50, 170);
}
The figure drawn in this applet is

A) a blue square
B) a blue square with two white lines drawn horizontally through it
C) a blue square with two white lines drawn diagonally through it
D) a blue square with two white lines drawn vertically through it
E) a white square with two blue lines drawn vertically through it

Question 26

For the following questions, refer to the class defined below:
import java.util.Scanner;
public class Questions
{
public static void main(String[ ] args)
{
int x, y, z;
double average;
Scanner scan = new Scanner(System.in);
System.out.println("Enter an integer value");
x = scan.nextInt( );
System.out.println("Enter another integer value");
y = scan.nextInt( );
System.out.println("Enter a third integer value");
z = scan.nextInt( );
average = (x + y + z) / 3;
System.out.println("The result of my calculation is " + average);
}
}
Questions33_34 computes

A) The correct average of x, y and z as a double
B) The correct average of x, y and z as an int
C) The average of x, y, and z as a double, but the result may not be accurate
D) the sum of x, y and z
E) the remainder of the sum of x, y and z divided by 3

Question 27

Consider the double value likelihood = 0.013885. What would be output if DecimalFormat dformatter = DecimalFormat("0.00##"); and you execute System.out.println(df.format(likelihood)); ?

A) 0.013885
B) 0.0139
C) 0.014
D) )0139
E) )014

Question 28

In order to create a constant, you would use which of the following Java reserved words?

A) private
B) static
C) int
D) final
E) class

Question 29

Consider the following paint method and answer the questions below:
public void paint(Graphics page)
{
page.setColor(Color.blue);
page.fillRect(50, 50, 100, 100);
page.setColor(Color.white);
page.drawLine(50, 50, 150, 150);
page.drawLine(50, 150, 150, 50);
page.setColor(Color.black);
page.drawString("A nice box", 50, 170);
}
The String "A nice box" is drawn

A) above the box
B) to the left of the box
C) to the right of the box
D) below the box
E) inside the box

Question 30

You specify the shape of an oval in a Java applet by defining the oval's

A) arc locations
B) center and radius
C) bounding box
D) foci
E) none of the above, it is not possible to draw an oval in a Java applet

Question 31

What value will z have if we execute the following assignment statement?
Int z = 50 / 10.00;

A) 5
B) 5.0
C) 50
D) 10
E) none of the above, a run-time error arises because z is an int and 50 / 10.00 is not

Question 32

Since you cannot take the square root of a negative number, you might use which of the following instructions to find the square root of the variable x?

A) Math.sqrt(x*x);
B) Math.sqrt((int) x);
C) Math.sqrt(Math.abs(x));
D) Math.abs(Math.sqrt(x));
E) Math.sqrt(-x);

Question 33

Which library package would you import to use NumberFormat and DecimalFormat?

A) java.beans
B) java.io
C) java.lang
D) java.text
E) java.util

Question 34

If you want to output a double so that at least 1 digit appears to the left side of the decimal point and exactly 1 digit appears to the right side of the decimal point, which pattern would you give a DecimalFormat variable when you instantiate it?

A) "0.0"
B) "0.#"
C) "0.0#"
D) "0.##"
E) "#.#"

Question 35

Suppose that String name = "Frank Zappa". What will the instruction name.toUpperCase( ).replace('A', 'I'); return?

A) "FRANK ZAPPA "
B) "FRINK ZIPPI"
C) "Frink Zippi"
D) "Frank Zappa"
E) "FrInk ZIppI"

Question 36

If you want to draw a red circle inside of a green square in an applet where the paint method is passed a Graphics object called page, which of the following sets of commands might you use?

A) page.setColor(Color.green); page.fillRect(50, 50, 100, 100);
Page.setColor(Color.red);
Page.fillOval(60, 60, 80, 80);
B) page.setColor(Color.red); page.fillOval(60, 60, 80, 80);
Page.setColor(Color.green);
Page.fillRect(50, 50, 100, 100);
C) page.setColor(Color.green); page.fillRect(60, 60, 80, 80);
Page.setColor(Color.red);
Page.fillOval(50, 50, 100, 100);
D) page.setColor(Color.red); page.fillOval(50, 50, 100, 100);
Page.setColor(Color.green);
Page.fillRect(60, 60, 80, 80);
E) any of the above would accomplish this

Question 37

Using getCurrencyInstance( ) formats a variable, automatically inserting

A) decimal point for cents
B) dollar sign
C) percent sign
D) all three
E) A and B but not C

Question 38

If the String major = "Computer Science", what is returned by major.charAt(1)?

A) 'C'
B) 'o'
C) 'm'
D) "C"
E) "Computer"

Question 39

If a, b, and c are int variables with a = 5, b = 7, c = 12, then the statement int z = (a * b - c) / a; will result in z equal to

A) 0
B) 4
C) 5
D) -5
E) 23

Question 40

The Random class has a method nextFloat( ) which returns a random float value between

A) -1 and +1
B) 0 and 1
C) 0 and 99
D) 1 and 100
E) -2,147,483,648 and +2,147,483,647

Question 41

Many Java drawing shapes are specified using a bounding rectangle.

Question 42

In order to generate a random number, you must use Math.random( ).

Question 43

In Java, 'a' and 'A' are considered to be different values.

Question 44

Write a set of instructions to prompt the user for an int value and input it using the Scanner class into the variable x and prompt the user for a float value and input it using the Scanner class into the variable y.

Question 45

There are three ways that data conversion may occurby assignment, by promotion, by casting.

Question 46

If x is a string, then x = new String("OH"); and x = "OH"; will accomplish the same thing.

Question 47

Java is a strongly typed language. What is meant by "strongly typed"?

A) Every variable must have an associated type before you can use it
B) Variables can be used without declaring their type
C) Every variable has a single type associated with it throughout its existence in the program, and the variable can only store values of that type
D) Variables are allowed to change type during their existence in the program as long as the value it currently stores is of the type it is currently declared to be
E) Variables are allowed to change types during their existence in the program but only if the change is to a narrower type

Question 48

The values of (double) 5 / 2 and (double) (5 / 2) are identical.

Question 49

As presented in the Software Failure, the root cause of the Mars Climate Orbiter problem was

A) the cost of the project
B) an inability to track the orbiter at long distances
C) atmospheric friction
D) a communication issue between subsystems
E) none of the above

Question 50

If String a = "ABCD" and String b = "abcd" then a.equals(b); returns false but a.equalsIgnoreCase(b); returns True.

Question 51

A variable of type boolean will store either a 0 or a 1.

Question 52

A double is wider than a float and a float is wider than an int.

Question 53

Java is able to represent 255 * 255 * 255 = 16,581,375 distinct colors.

Question 54

Provide an example of how you might use a boolean, a float, a char, a String, and an int.

Question 55

If x is the String "Hi There", then x.toUpperCase( ).toLowerCase( ); will return the original version of x.

Question 56

You cannot cast a String to be a char and you cannot cast a String which stores a number to be an int, float or double.

Question 57

The Java graphics coordinate system is similar to the coordinate system one finds in mathematics in every respect.

Question 58

Unlike the String class where you must pass a message to an object (instance) of the class, as in x.length( ), in order to use either the Scanner or Math classes, you pass messages directly to the class name, as in Math.abs( ) or scan.nextInt( ).

Question 59

As explained in the Software Failure, the Mars Lander most likely crash landed when its descent engines cut off too high over the Mars surface.

Question 60

If String name = "George W. Bush"; then the instruction name.length( ); will return 14.

Question 61

What is wrong with the following assignment statement?
Assume x and y are both String objects.
String z = x.equals(y);

Question 62

Write an output statement which will output the following characters exactly as shown: / ' \" / ' \

Question 63

What are the syntax errors from the following program?
public class Enigma
{
public static void main(String[ ] args)
{
System.out.println("Input a String");
String x = scan.nextString( );
int size = x.length;
char last = x.charAt(size);
System.out.println("The last character in your string ", x, " is ", last);
}
}

Question 64

Given two points in an applet represented by the four int variables x1, y1, x2 and y2, write a paint method to draw a line between the two points and write the location of the two points next to the two points.

Question 65

Assume that a = "1", b = "2", y = 3 and z = 4. How do the following two statements differ?
System.out.println(a + b + y + z);
System.out.println(y + z + a + b);

Question 66

Using the various String methods, manipulate a String called current to be current's last character followed by the remainder of its characters in order, placing the result in a String called rearranged.

Question 67

Provide three examples of code using assignment statements where one assignment statement would result in a syntax error, one would result in a logical error, and one would result in a run-time error.

Question 68

An applet is 200x200. Write the Strings "North", "South", "East", and "West" at the four edges of the applet where they should appear as if on a map. Use the color black for the text.

Question 69

An employer has decided to award a weekly pay raise to all employees by taking the square root of the difference between his weight and the employee's weight. For instance, an employee who weighs 16 pounds less than the employer will get a $4 per week raise. The raise should be in whole dollars (an int). Assume that employerWeight and employeeWeight are both int variables that have been input, write an assignment statement to compute the int value for raise.

Question 70

How many ways are there to test to see if two String variables, a and b, are equal to each other if we ignore their case (for instance, "aBCd" would be considered equal to "ABcd").

Question 71

Write a program which will input an int value x, and compute and output the values of 2ˣ and x¹⁰ as int values.

Question 72

How do the statements "import java.util.*;" and "import java.util.Random;" differ from each other?

Question 73

Given four int values, x1, x2, y1, y2, write the code to compute the distance between the two points (x1, y1) and (x2, y2), storing the result in the double distance.

Question 74

Write an assignment statement to compute the gas mileage of a car where the int values miles_traveled and gallons_needed have already been input. The variable gas_mileage needs to be declared and should be a double.

Question 75

Explain, in words, what the following statement computes:
int z = (int) Math.ceil(Math.sqrt(x) / Math.sqrt(y));

Question 76

Write the paint method for an applet so that it contains 4 concentric circles (each circle is inside the previous circle), where the largest circle is bounded by a 400x400 box and the smallest is bounded by a 100x100 box. Each circle is centered on an applet that is 400x400. Make each circle a different color of your choice.

Question 77

Write a program that will input some number of cents (less than 100) and output the number of quarters, dimes, nickels and pennies needed to add up to that amount.