Deck 7: Characters Strings and the Stringbuilder

Question 1

When you compare String s with the == operator, you are comparing their values, not their memory addresses.

Answer 1

False

Question 2

Any string value that is input into a program can be used in arithmetic operations.

Answer 2

False

Question 3

In a compareTo() method, programmers often do not need specific return values but want to determine if a value is positive or negative.

Answer 3

True

Question 4

A(n) ____ comparison is based on the integer Unicode values of the characters.

A) integer
B) symbol
C) lexicographical
D) character

Question 5

When working with String s, it is necessary to explicitly set a String to null .

Question 6

The Character class ____ from java.lang.Object .

A) calls
B) inherits
C) refers
D) spawns

Question 7

The StringBuffer class is more efficient than the StringBuilder class because it can execute multiple threads during program execution.

Question 8

A ____ is a class for storing and manipulating changeable data that is composed of multiple characters.

A) Character
B) String
C) StringVariable
D) StringBuilder

Question 9

A(n) ____ is a variable that holds a memory address.

A) reference
B) Character
C) buffer
D) immutable

Question 10

The String class ____ method evaluates the contents of two String objects to determine if they are equivalent.

A) equals()
B) toString()
C) charAt()
D) replace ()

Question 11

The method header of the equals() method within the String class is ____.

A) public boolean equals(Strings)
B) private boolean equals(String s)
C) public boolean equals(String s)
D) public boolean equals(Character s)

Question 12

If you try to use an index that is less than 0 or less than the index of the last position in the StringBuilder object, you cause an error known as an exception and your program terminates.

Question 13

The terms "literal string" and "string literal" are entirely different in Java programming.

Question 14

A String variable name is not a simple data type.

Question 15

When you must determine whether a String is empty, it is more efficient to compare its length to 0 than it is to use the equals () method.

Question 16

String s and other objects that can't be changed are known as ____.

A) string constants
B) accessor methods
C) immutable
D) garbage

Question 17

When you declare a variable of a basic, primitive type, such as int x = 10; , the memory address where x is located holds the ____.

A) location in memory of 10
B) memory address of 10
C) reference to 10
D) value of 10

Question 18

When using the prewritten equals() method, a true or false comparison between two String s is returned, but you do not know how the code looks behind the scenes.

Question 19

The methods of the Character class that begin with ____ return a character that has been converted to the stated format.

A) is
B) to
C) for
D) in

Question 20

A literal string is a(n) ____ object.

A) lost
B) anonymous
C) class
D) named

Question 21

System.out.println("Your name is " + yourName); The above statement is an example of ____, which is used to join String s.

A) concatenation
B) referencing
C) parsing
D) buffering

Question 22

In Java, a(n) ____________________ is a class or object that is wrapped around a simpler element.

Question 23

The ____ method returns the length of a String .

A) getSize()
B) getLength()
C) size()
D) length()

Question 24

Which of the following correctly declares and initializes a String object?

A) new String = Hello
B) String greeting == "Hello";
C) String greeting = "Hello";
D) String new = "Hello"

Question 25

The ____ method lets you add characters at a specific location within a StringBuilder object.

A) charAt()
B) insert()
C) append()
D) setCharAt()

Question 26

The ____ method converts any object to a String .

A) convertString()
B) toString()
C) replace()
D) substring()

Question 27

The creators of Java chose ____ characters as the "extra" length for a StringBuilder object.

A) 12
B) 16
C) 36
D) 48

Question 28

The ____________________ class contains standard methods for testing the values of characters.

Question 29

The ____ method allows you to replace all occurrences of some character within a String .

A) substring()
B) toString()
C) replaceCharacter()
D) replace()

Question 30

You can tell that the equals() method takes a ____ argument because parentheses are used in the method call.

A) String
B) Null
C) Double
D) Boolean

Question 31

When the String class ____ method is used to compare two String s, it provides additional information to the user in the form of an integer value.

A) toString()
B) compareTo()
C) equals()
D) equalsIgnoreCase()

Question 32

The String class ____________________ method is similar to the equals() method. As its name implies, this method ignores case when determining if two String s are equivalent.

Question 33

The ____________________ method requires an integer argument that indicates the position of the character at that position, starting at 0.

Question 34

The ____ method takes a String argument and returns its double value.

A) parseString()
B) parseInt()
C) parseDouble()
D) returnDouble()

Question 35

String oneStr = "Welcome Jim" String twoStr = "Welcome Joe"
Given the lines of code above, which of the following regionMatches() expressions will result in a value of true ?

A) oneStr.regionMatches(8, twoStr, 8, 3)
B) oneStr.regionMatches(0, twoStr, 0, 7)
C) oneStr.regionMatches(8, twoStr, 0, 3)
D) oneStr.regionMatches(0, twoStr, 8, 3)

Question 36

To alter just one character in a StringBuilder , you can use the ____ method, which allows you to change a character at a specified position within a StringBuilder object.

A) charAt()
B) insert()
C) append()
D) setCharAt()

Question 37

A StringBuilder object contains a memory block called a _____, which might or might not contain a string.

A) capacity
B) buffer
C) reference
D) thread

Question 38

The ____________________ method and the startsWith() method each take a String argument and return true or false if a String object does or does not end or start with the specified argument, respectively.

Question 39

To convert a String to an integer, you use the ____ class, which is part of java.lang and is automatically imported into programs you write.

A) StringBuilder
B) String
C) Integer
D) Convert

Question 40

Besides Double and Integer , other wrapper classes such as Float and Long also provide ____ methods that convert String s to the wrapper types.

A) valueOf()
B) toWrapper()
C) parseString()
D) parseDouble()

Question 41

String aName = "Michael"
Using the above statement, write the length() method that will return the length of the aName String . What value will the length() method return when executed?

Question 43

yourCounty = "perry";
yourCounty.equals("Perry");
yourCounty.equalsIgnoreCase("Perry");
Using the above statements, what value will be returned by the equals() method? What will be the value of the equalsIgnoreCase() method? Explain how the equalsIgnoreCase() method can be useful when users type responses to prompts in programs.

Question 44

Describe how a programmer would use the two types of Character class methods (those that begin with "is" and those that begin with "to") for testing the values of characters.

Question 45

In the above code, two strings are evaluated using the equivalency operator. Why can this be a problem, and what other methods are offered by Java for working with characters and strings?

Question 46

What is the purpose of the substring() method and how do you use it?

Question 47

How is the String class equalsIgnoreCase() method like the equals() method and how would you use it? Give an example.

Question 48

String greeting = "Welcome back";
Using the above statement, write the length() method that will return the length of the greeting String . Store the length in an integer named greetingLength .

Question 49

StringBuilder greeting = new StringBuilder("Welcome home ");
phrase.insert(13, "Joe");
Using the above code and insert() method, describe how the phrase will appear after the code executes. How does the insert() method work?

Question 50

String greeting = "Welcome Home";
Using the above String , create the String method to convert the greeting String to all uppercase. Likewise, create the String method to convert the greeting String to all lowercase.

Question 51

Describe how a string is a reference and how a string comparison is done.

Question 52

StringBuilder greeting = new StringBuilder("Hello, John");
char initial = greeting.charAt(7);
Using the above code and the charAt() method, what value will be assigned to the variable initial ?

Question 53

What happens when you increase a StringBuilder object's length to be longer than the string it holds? What happens if you set the length of a string to be shorter than the string it contains?

Question 54

What is the purpose of the replace() method? Provide an example.

Question 55

How can you change the length of a String in a StringBuilder object?

Question 56

How can you use String methods to change the case of a string? Provide an example.

Question 57

String example1 = "";
String example2 = null;
String example3;
There is an important difference between empty String s and null String s. Explain the differences and why it is important when making String comparisons.

Question 58

String firstString = "Oak Maple Pine"
String secondString = "spruce Maple elm"
firstCompare.regionMatches(4, secondString, 7, 5)
Using the above code, what will be the Boolean value after execution of the regionMatches statement? Explain how the String s are compared using the regionMatches() method.

Question 59

Explain what is needed to declare a String variable and provide an example.

Question 60

Why would you use the append() method? Provide an example.

Question 61

StringBuilder greeting = new StringBuilder("Welcome");
Use the append() method to add the characters "home" to the end of the StringBuilder object created above.

Question 62

yourCounty = "Clark"
yourCounty.startsWith("Cla")
What value will be returned by the startsWith() method? Explain how the startsWith() method deals with case sensitivity.

Question 63

import javax.swing.JOptionPane;
public class Practice
{
    public static void main(String[] args)
    {
     String fullName;
     char firstLetter;
____
____
    }
}
Accepting a String from a user is common practice. Using the above code, write the statements to accept a String response from a user. Prompt the user with "Enter your name". Then use the charAt() method to extract the first character of the String .

Question 64

What is a wrapper and why would you use it?

Question 65

StringBuilder greeting = new StringBuilder("Day 1");
Using the above StringBuilder , create a setCharAt() method that will change the "1" to a "2" in the String "Day 1" . Explain how the setCharAt() method operates.

Question 66

String s  and other objects that can't be changed are said to be immutable. What does this mean and how does it relate to values held in memory addresses?

Question 67

Give a code example of using the equivalence operator ("==") to compare the addresses of two strings where the comparison will result in the value true . The example should produce output indicating the strings have the same value.

Question 68

myCounty = "Clark Jackson Scioto"
myCounty.charAt(6)
Using the above code, what will be the value of the charAt() method once the code executes? Explain how the charAt() method operates.