Deck 14: Strings, Characters and Regular Expressions

Question 1

A String constructor cannot be passed ________.

A) char arrays.
B) int arrays.
C) byte arrays.
D) Strings.

Answer 1

int arrays.

Question 2

An anonymous String ________.

A) has no value
B) is a string literal
C) can be changed
D) none of the above

Answer 2

is a string literal

Question 3

Which of the following will create a String different from the other three?

A) String r = "123456"
B) int i = 123; int j = 456;
String r = String.valueOf(j) + String.valueOf(i);
C) int i = 123; int j = 456;
String r = String.valueOf(i) + String.valueOf(j);
D) int i = 123; int j = 456;
String r = i + j;

Answer 3

B

Question 4

Consider the String below:
String r = "a toyota";
Which of the following will create the String r1 = "a TOYOTa"?

A) String r1 = r.replace("toyot", TOYOT");
B) String r1 = r.replace('t','T');
r1 = r.replace('o','0');
r1 = r.replace('y','Y');
C) String r1 = r.replace('t','T').replace('o', '0').replace('y', 'Y');
D) String r1 = r.substring(2, 4).toUpperCase();

Question 5

Consider the examples below: A. a string.
B) 'a string'.
C) "a string".
D) "1234".
E) integer.
Which could be the value of a Java variable of type String?

A) A and B.
B) B and E.
C) B and C.
D) C and D.

Question 6

How many String objects are instantiated by the following code segment (not including the literals)?
String s1, output;
S1 = "hello";
Output = "\nThe string reversed is: " ;
For (int i = s1.length() - 1; i >= 0; i--)
Output += s1.charAt(i) + " " ;

A) 1.
B) 4.
C) 5.
D) 7.

Question 7

Which of the following is not a method of class String?

A) toUpperCase
B) trim
C) toCharacterArray
D) All of the above are methods of class String

Question 8

The statement
s1.equalsIgnoreCase(s4)
Is equivalent to which of the following?

A) s1.regionMatches(true, 0, s4, 0, s4.length());
B) s1.regionMatches(0, s4, 0, s4.length());
C) s1.regionMatches(0, s4, 0, s4.length);
D) s1.regionMatches(true, s4, 0, s4.length);

Question 9

The length of a string can be determined by ________.

A) the String method length()
B) the String instance variable length
C) the String method strlen()
D) All of the above.

Question 10

Consider the statement below:
StringBuilder sb1 = new StringBuilder("a toyota");
Which of the following creates a String object with the value "toy"?

A) String res = sb1.subString(2, 5);
B) char dest[] = new char[sb1.length()]; sb1.getChars(2, 5, dest, 0);
String res = new String(dest);
C) char dest[] = new char[sb1.length]; dest = sb1.getChars(2, 5);
String res = new String(dest);
D) char dest[] = new char[sb1.length()]; dest = sb1.getChars(0, 3);
String res = new String(dest);

Question 11

Given the following declarations:
StringBuilder buf;
StringBuilder buf2 = new StringBuilder();
String c = new String("test");
Which of the following is not a valid StringBuilder constructor?

A) buf = new StringBuilder();
B) buf = new StringBuilder(buf2, 32);
C) buf = new StringBuilder(32);
D) buf = new StringBuilder(c);

Question 12

To find the character at a certain index position within a String, use the method ________.

A) getChars, with the index as an argument
B) getCharAt, with the index as an argument
C) charAt, with the index as an argument
D) charAt, with the character you are searching for as an argument

Question 13

Consider the statements below:
StringBuilder sb = new StringBuilder("a toyota");
Sb)insert(2, "landrover");
Sb)delete(11, 16);
Sb)insert(11, " ");
The StringBuilder contents at the end of this segment will be ________.

A) a landrovertoyota
B) a landrover a
C) a landrov a
D) a landrover toy a

Question 14

Given the following declaration:
StringBuilder buf = new StringBuilder();
What is the capacity of buf?

A) 0
B) 10
C) 16
D) 20

Question 15

StringBuilder objects can be used in place of String objects if ________.

A) the string data is not constant
B) the string data size may grow
C) the programs frequently perform string concatenation
D) All of the above.

Question 16

The statement
s1.startsWith("art")
Has the same result as which of the following?

A) s1.regionMatches(0, "art", 0, 3);
B) s2 = s1.getChars(0, 3); s2.equals("art");
C) s1.regionMatches(true, 0, "art", 0, 3);
D) All of the above

Question 17

Which of the following statements is true?

A) The capacity of a StringBuilder is equal to its length.
B) The capacity of a StringBuilder cannot exceed its length.
C) The length of a StringBuilder cannot exceed its capacity.
D) Both a and b are true.

Question 18

String objects are immutable. This means they ________.

A) must be initialized
B) cannot be deleted
C) cannot be changed
D) None of the abov

Question 19

Given the following declarations:
StringBuilder buffer = new StringBuilder("Testing Testing");
Buffer.setLength(7);
Buffer.ensureCapacity(5);
Which of the following is true?

A) buffer has capacity 5.
B) buffer has capacity 31.
C) buffer has content "Testin".
D) buffer has length 15.

Question 20

Which of the following creates the string of the numbers from 1 to 1000 most efficiently?

A) String s;
for (int i = 1; i <= 1000; i++)
S += i;
B) StringBuilder sb = new StringBuilder(10);
for (int i = 1; i <= 1000; i++)
Sb)append(i);
String s = new String(sb);
C) StringBuilder sb = new StringBuilder(3000);
for (int i = 1; i <= 1000; i++)
Sb)append(i);
String s = new String(sb);
D) All are equivalently efficient.

Question 21

Which of the following statements is true?

A) Ranges of characters can be represented by placing a ~ between two characters.
B) [^Z] is the same as [A~Y].
C) Both "A*" and "A+" will match "AAA", but only "A*" will match an empty string.
D) All of above.

Question 22

Consider the Java segment:
String line1 = new String("c = 1 + 2 + 3") ;
StringTokenizer tok = new StringTokenizer(line1, delimArg);
For the String line1 to have 4 tokens, delimArg should be:

A) String delimArg = "+=";
B) String delimArg = "123"
C) String delimArg = "c+";
D) String delimArg = " ";

Question 23

Consider the Java segment:
String line1 = new String("c = 1 + 2 + 3") ;
StringTokenizer tok = new StringTokenizer(line1, "+=");
String foo = tok.nextToken();
String bar = tok.nextToken();
The values of foo and bar are:

A) foo is "c ", bar is " = ".
B) foo is "c", bar is " ".
C) foo is " = ", bar is " + ".
D) foo is "c ", bar is " 1 ".

Question 24

Which class is not a type-wrapper class?

A) Character
B) Int
C) Double
D) Byte

Question 25

Which of the following are static Character methods?

A) Character.hashcode(char c);
B) Character.isDigit(char c);
C) Character.equals(char c);
D) All of the above.

Question 26

Consider the Java segment:
String line1 = new String("c = 1 + 2 + 3") ;
StringTokenizer tok = new StringTokenizer(line1);
Int count = tok.countTokens();
The value of count is ________.

A) 8.
B) 7.
C) 13.
D) 4.