Deck 2: Data and Expressions

Question 1

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

Answer 1

True

Question 2

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

Answer 2

False

Question 3

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

Answer 3

True

Question 4

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

Question 5

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

Question 6

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 7

If you want to output the text "hi there" including the quote marks, which of the following would you use?

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 of these; it is not possible to output a quote mark because it is used to mark the beginning and end of the String to be displayed.

Question 8

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

Question 9

Example Code Ch 02-1
public class Questions1_4
{
public static void main(String[] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
Refer to the class definition in Example Code Ch 02-1. How many lines of output are provided by this program?

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

Question 10

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

Question 11

Example Code Ch 02-1
public class Questions1_4
{
public static void main(String[] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
Refer to the class definition in Example Code Ch 02-1. 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 12

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

Question 13

There are three ways that data conversion may occur: by assignment, by promotion, and by casting.

Question 14

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 15

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

Question 16

The following statement will output __________ lines of text. System.out.println("1 big bad wolf\t8 the 3 little pigs\n4
Dinner\r2night");

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

Question 17

Example Code Ch 02-1
public class Questions1_4
{
public static void main(String[] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
Refer to the class definition in Example Code Ch 02-1. The program will print the word "Here" and then print

A) "There Everywhere" on the line after "Here"
B) "The" 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 18

The word println is a(n)

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

Question 19

Example Code Ch 02-1
public class Questions1_4
{
public static void main(String[] args)
{
System.out.print("Here");
System.out.println("There " + "Everywhere");
System.out.println("But not" + "in Texas");
}
}
Refer to the class definition in Example Code Ch 02-1. 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

Question 20

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

Question 21

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 22

Assume that x and y are ints equal to 10 and 5 respectively. What is the output of the following statement? System.out.println(x + y);

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

Question 23

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 24

A Java variable is the name of a

A) numeric data value stored in memory
B) data value stored in memory that cannot 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 25

Given String name = "Arleen Crabtree". What will the following instruction return? name.toUpperCase().replace('R', 'Z');

A) "ARLEEN CRABTREE"
B) "AZLEEN CZABTREE"
C) "Azleen Czabtree"
D) "Arleen Crabtree"
E) "ArZleen CrZabtree"

Question 26

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

A) int
B) double
C) float
D) char
E) All of these can store numeric values

Question 27

If x is an int and y is a float, which of the following statements is not a legal assignment statement?

A) y = x;
B) x = y;
C) y = (float)x;
D) x = (int)y;
E) All of these are legal assignment statements

Question 28

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

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

Question 29

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 30

Assume that x, y, and z are all ints equal to 50, 20, and 6 respectively. What is the result of: x / y / z

A) 0
B) 12
C) 16
D) this would cause a syntax error
E) this would cause a run-time error because it is a division by zero

Question 31

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;
E) x.charAt(x.length());

Question 32

What is the value of z after the following assignment statement is executed? float z = 5/10;

A) 0.0
B) 0.5
C) 5.0
D) 0.05
E) None of these; a run-time error will occur because z is a float and 5/10 is an int.

Question 33

Given the double likelihood = 0.013885 and given DecimalFormat dformatter = DecimalFormat("0.00##");
What would be the output if you execute the following:
System.out.println(df.format(likelihood));

A) 0.013885
B) 0.0139
C) 0.0145
D) .0138
E) .014

Question 34

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

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

Question 35

Assume that x and y are ints equal to 10 and 5 respectively. What is the output of the following statement? System.out.println("" + x + y);

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

Question 36

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 its result is always numeric.

Question 37

Which of the following situations would require a cast?

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 these require casts

Question 38

If you want to store the value "Harry Potter" in the String variable name, which of the following statements could you use?

A) String name = "Harry Potter";
B) String name = new String("Harry Potter");
C) String name = "Harry" + " " + "Potter";
D) String name = new String("Harry" + " " + "Potter");
E) Any of these would work

Question 39

Using getCurrencyInstance() formats a variable, automatically inserting

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

Question 40

What will be the result of the following assignment statement, given that b = 5 and c = 10? int a = b * (-c + 2)/2;

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

Question 41

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

Question 42

Given three int variables with the values a = 5, b = 7, and c = 12, what is the value of z after the following statement is executed? int z = (a * b - c) / a;

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

Question 43

As presented in the Software Failure section of the text, 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 these

Question 44

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

Question 45

Example Code Ch 02-2
import java.util.Scanner;
public class Questions33_34
{
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);
}
}
Refer to Example Code Ch 02-2. What is the output if x = 0, y = 1, and z = 1?

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

Question 46

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 47

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

Question 48

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 49

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 50

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 51

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

Question 52

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

A) Every variable must have an associated type before it can be used.
B) Variables can be used without declaring their types.
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 a program so long as the value a variable currently stores is of the type it currently declared to be.
E) Variables are allowed to change types during their existence in a program but only if the change is to a narrower type.

Question 53

Since you cannot take the square root of a negative number, which of the following could you use 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 54

Given x is a double and has the value 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.format(x));
D) System.out.println(nf.x);
E) System.out.println(format(x));

Question 55

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 56

Example Code Ch 02-2
import java.util.Scanner;
public class Questions33_34
{
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);
}
}
Refer to Example Code Ch 02-2. This code 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 as an int
E) The remainder of the sum of x, y, and z divided by 3

Question 57

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 58

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

Question 59

What will be the value of z after the following statement is executed? int z = 50 /10.00;

A) 5
B) 5.0
C) 50
D) 10
E) None of thse; a run-time error will occur because z is an int and 50/10.00 is not

Question 60

In order to create a constant, which of the following Java reserved words is used?

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

Question 61

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.

Question 62

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 63

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

Question 64

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

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

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 67

Write a program which will input an int value, x, and compute and output the values of 2^x and x^10 as int values.