Deck 16: Strings

Question 1

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.

Answer 1

C

Question 2

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 2

B

Question 3

The String method substring returns:

A)A char.
B)A String.
C)void.
D)A char[].

Answer 3

B

Question 4

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 5

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 6

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 7

An anonymous String:

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

Question 8

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 9

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

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

Question 10

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 11

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 12

String objects are immutable.This means they:

A)Must be initialized.
B)Cannot be deleted.
C)Cannot be changed.
D)None of the above

Question 13

A String constructor cannot be passed variables of type:

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

Question 14

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 15

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 16

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 17

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 18

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 19

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 20

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 21

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 22

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 23

Which class is not a type-wrapper class?

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

Question 24

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 25

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 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.