Question 1

What would be the results of executing the following code?
StringBuilder str = new StringBuilder("Little Jack Horner ");
Str)append("sat on the ");
Str)append("corner");
A) The program would crash.
B) str would reference "Little Jack Horner ".
C) str would reference "Little Jac Horner sat on the ".
D) str would reference "Little Jack Horner sat on the corner".

Accepted Answer

The code first initializes a StringBuilder object with the value "Little Jack Horner ". Then, the append() method is called twice on this StringBuilder object, with the arguments "sat on the " and "corner", respectively. Each call to append() adds the specified string to the end of the StringBuilder object's current value. Therefore, after the second append() call, the StringBuilder object's value would be "Little Jack Horner sat on the corner".

Question 2

If your program needs to make a lot of changes to one or more string, you might consider using objects of this class:
A) Character
B) String
C) StringBuilder
D) All of the above

Accepted Answer

The StringBuilder class is specifically designed for making changes to a string without creating a new object every time a change is made. This is much more efficient than using the Character or String classes, which create new objects each time a change is made. Therefore, if your program needs to make a lot of changes to one or more strings, StringBuilder is the best choice.

Question 3

Which of the following methods of the String class can be used to tokenize a string?
A) split
B) tokenize
C) trim
D) length

Accepted Answer

The method "split" can be used to tokenize a string by dividing it into an array of substrings based on a specified delimiter, which can be a regular expression or a string. The other methods listed, "tokenize", "trim", and "length", do not have the same functionality for tokenization.

Question 4

What will be printed after the following code is executed?
String str = "abc456";
Int m = 0;
While ( m < 6 )
{
If (Character.isLetter(str.charAt(m)))
System.out.print(
Character.toUpperCase(str.charAt(m)));
M++;
}
A) abc456
B) ABC456
C) ABC
D) 456

Accepted Answer

The code checks each character of the string "abc456" to determine if it is a letter. If it is, it converts it to uppercase and prints it. Since only "abc" are letters, only "ABC" is printed.

Question 5

In the following statement, what data type must recField be?
Str)getChars(5, 10, recField, 0);
A) String
B) int
C) char
D) char[]

Accepted Answer

The getChars() method is used to copy characters from a specified string into an array of characters. Therefore, recField must be an array of characters (char[]), which is option D.

Question 6

What will be the tokens for the following code?
String str = "123-456-7890";
String[] tokens = str.split("-");
A) 123, 456, and 7890
B) -
C) 123, 456, 7890, and -
D) None of the above

Accepted Answer

The code splits the string "123-456-7890" into tokens based on the delimiter "-", resulting in the tokens "123", "456", and "7890".

Question 7

When you are writing a program with String objects that may have unwanted spaces at the beginning or end of the strings, use this method to delete them.
A) replace
B) trim
C) valueOf
D) substring

Accepted Answer

The method to delete unwanted spaces at the beginning or end of a String object is `trim()`. This method removes whitespace characters from both the beginning and the end of the string. The other options do not have the desired functionality. `replace()` and `substring()` can replace or extract characters from a string but do not remove whitespace characters. `valueOf()` is used to convert data types into string objects.

Question 8

Sometimes a string will contain a series of words or other items of data separated by spaces or other characters. In programming terms, items such as these are known as what?
A) Tokens
B) Delimiters
C) Key characters
D) Lists

Accepted Answer

These items are commonly referred to as tokens in programming.

Question 9

When using the StringBuilder class's insert method, you can insert:
A) any primitive type
B) a String object
C) a char array
D) All of the above

Accepted Answer

The StringBuilder class's insert method can be used to insert any primitive type, a String object, or a char array, so the best choice is D, which includes all of these options.

Question 10

What is the term used for the character that separates tokens?
A) tokenizer
B) delimiter
C) whitespace
D) separator

Accepted Answer

The term used for the character that separates tokens is the delimiter. A tokenizer is a program or function that breaks down input into individual tokens. Whitespace and separators are related but do not specifically refer to the characters used to separate tokens.

Question 11

What will be the value of matches after the following code is executed?
Boolean matches;
String[] productCodes = {"456HI345", "3456hj"};
Matches = productCodes[0].regionMatches(true, 1,
ProductCodes[1], 2, 3);
A) 56H
B) 56h
C) true
D) False

Accepted Answer

The regionMatches() method compares a region of one string with a region of another string. In this case, it will compare "56HI" from the first string "456HI345" with "56h" from the second string "3456hj". Since it is case-insensitive (as indicated by the "true" parameter), the method will return "true" indicating that the regions match. This value is then assigned to the Boolean variable "matches". Therefore, the value of "matches" will be "true".

Question 12

Assuming that str is declared as follows: String str = "RSTUVWXYZ";
What value will be returned from str.charAt(5)?
A) U
B) V
C) W
D) X

Accepted Answer

The method charAt(5) returns the character at index 5 of the string "RSTUVWXYZ", which is 'W'.

Question 13

Look at the following statement: StringBuilder str = new StringBuilder(25);
What will the StringBuilder constructor do?
A) give the object, str, 25 bytes of storage and store spaces in them
B) give the object, str, 25 bytes of storage and not store anything in them
C) give the object, str, 25 or more bytes of storage and store spaces in them
D) give the object, str, 0 bytes of storage

Accepted Answer

The StringBuilder constructor with an integer argument initializes the object with a capacity of 25, meaning it can hold 25 characters, but it does not store any characters initially.

Question 14

What will be the value of loc after the following code is executed?
Int loc;
String str = "The cow jumped over the moon.";
Loc = str.indexOf("ov");
A) 15
B) 16
C) 17
D) 18

Accepted Answer

The method indexOf("ov") returns the index of the first occurrence of the substring "ov" in the string, which starts at index 15.

Question 15

The Character wrapper class provides numerous methods for:
A) testing String objects
B) testing and converting char variables
C) converting String variables
D) adding two char variables

Accepted Answer

The Character wrapper class provides methods for testing and converting char variables, such as isDigit(char ch), isLetter(char ch), toUpperCase(char ch), and toLowerCase(char ch). It does not provide methods for testing or converting String objects, adding two char variables or converting String variables.

Question 16

What is term used for a class that is "wrapped around" a primitive data type and allows you to create objects instead of variables?
A) Intrinsic class
B) Enclosed object
C) Wrapper class
D) Transitional object

Accepted Answer

This type of class is called a wrapper class because it "wraps" around a primitive data type and allows you to create objects of that type. Examples of wrapper classes in Java include Integer, Double, and Boolean.

Question 17

What will be the value of str after the following statements are executed?
StringBuilder str =
New StringBuilder("We have lived in Chicago, " +
"Trenton, and Atlanta.");
Str)replace(17, 24, "Tampa");
A) We have lived in Tampa, Trenton, and Atlanta.
B) We have lived in Chicago, Tampa, and Atlanta.
C) We have lived in Tampa Trenton, and Tampa.
D) We have lived in Tampalanta.

Accepted Answer

The replace method replaces the substring from index 17 to 24 with "Tampa", resulting in "We have lived in Tampa, Trenton, and Atlanta.".

Question 18

The term ________ commonly is used to refer to a string that is part of another string.
A) strand
B) substring
C) character fragment
D) nested string

Accepted Answer

The term "substring" is commonly used to refer to a string that is part of another string. While "strand" can refer to a part of a larger structure or entity, it does not specifically refer to a string within a string. "Character fragment" is not a commonly used term in programming, and "nested string" generally refers to a string within another string, rather than a specific part of it.

Question 19

The process of breaking a string down into tokens is known as what?
A) tokenizing
B) buffering
C) simplifying
D) parsing

Accepted Answer

Tokenizing is the specific term used to describe the process of breaking a string down into smaller, meaningful pieces called tokens. Buffering refers to the process of temporarily storing data in a buffer, simplifying doesn't accurately describe this process, and parsing is a broader term encompassing various types of analysis of a string or document.

Question 20

This character is one that appears at the end, or right side, of a string, after the non-space characters:
A) Leading whitespace
B) Carriage return
C) Trailing whitespace
D) Line feed

Accepted Answer

Trailing whitespace refers to any space character that appears at the end (or right side) of a string after the non-space characters. This can include a space, tab, or any other whitespace character. Leading whitespace refers to whitespace characters that appear before the non-space characters in a string. Carriage return and line feed characters refer to specific control characters used for formatting and are not related to whitespace.

Quiz 9: Text Processing and More About Wrapper Classes

What would be the results of executing the following code? StringBuilder str = new StringBuilder("Little Jack Horner ") ; Str) append("sat on the ") ; Str) append("corner") ;

If your program needs to make a lot of changes to one or more string, you might consider using objects of this class:

Which of the following methods of the String class can be used to tokenize a string?

What will be printed after the following code is executed? String str = "abc456"; Int m = 0; While ( m < 6 ) { If (Character.isLetter(str.charAt(m) ) ) System.out.print( Character.toUpperCase(str.charAt(m) ) ) ; M++; }

In the following statement, what data type must recField be? Str) getChars(5, 10, recField, 0) ;

What will be the tokens for the following code? String str = "123-456-7890"; String[] tokens = str.split("-") ;

When you are writing a program with String objects that may have unwanted spaces at the beginning or end of the strings, use this method to delete them.

Sometimes a string will contain a series of words or other items of data separated by spaces or other characters. In programming terms, items such as these are known as what?

When using the StringBuilder class's insert method, you can insert:

What is the term used for the character that separates tokens?

What will be the value of matches after the following code is executed? Boolean matches; String[] productCodes = {"456HI345", "3456hj"}; Matches = productCodes[0].regionMatches(true, 1, ProductCodes[1], 2, 3) ;

Assuming that str is declared as follows: String str = "RSTUVWXYZ"; What value will be returned from str.charAt(5) ?

Look at the following statement: StringBuilder str = new StringBuilder(25) ; What will the StringBuilder constructor do?

What will be the value of loc after the following code is executed? Int loc; String str = "The cow jumped over the moon."; Loc = str.indexOf("ov") ;

The Character wrapper class provides numerous methods for:

What is term used for a class that is "wrapped around" a primitive data type and allows you to create objects instead of variables?

What will be the value of str after the following statements are executed? StringBuilder str = New StringBuilder("We have lived in Chicago, " + "Trenton, and Atlanta.") ; Str) replace(17, 24, "Tampa") ;

The term ________ commonly is used to refer to a string that is part of another string.

The process of breaking a string down into tokens is known as what?

This character is one that appears at the end, or right side, of a string, after the non-space characters: