test1

Class StringUtil

java.lang.Object

test1.StringUtil

public class StringUtil
extends Object

A utility class for working with strings.

Field Summary

Fields

Modifier and Type	Field and Description
static String	TEST_VERSION The version of this test.

Method Summary

Modifier and Type	Method and Description
static int	distance(String s, String t) Computes the number of characters that are different in two strings of equal length.
static String	join(String s, String t, String sep) Returns the string formed by concatenating the argument strings s and t with a separator string between them.
static char	mostFrequentChar(String s) Returns the character that appears most frequently in the string s.
static String	shortest(String s, String t) Returns the shortest of the two strings s and t.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TEST_VERSION

public static final String TEST_VERSION

The version of this test.

See Also:

Constant Field Values

Method Detail

join

public static String join(String s,
                          String t,
                          String sep)

Returns the string formed by concatenating the argument strings s and t with a separator string between them. For example:

 Utility2B.join("abc", "xyz", ":")
 

returns the string "abc:xyz".

Parameters:

s - a non-null string

t - a non-null string

sep - a non-null separator string

Returns:

the string formed by concatenating s followed by sep followed by t

shortest

public static String shortest(String s,
                              String t)

Returns the shortest of the two strings s and t. For example, shortest("python", "java") returns the string "java" because the string "java" is shorter than the string "python".

Parameters:

s - a non-null string

t - a non-null string

Returns:

the shortest of the two strings s and t

Throws:

IllegalArgumentException - if s and t have the same length

distance

public static int distance(String s,
                           String t)

Computes the number of characters that are different in two strings of equal length. The strings are compared character by character and the number of characters that differ is returned. For example:

 distance("talk", "talk")    returns  0
 distance("talk", "walk")    returns  1
 distance("well", "walk")    returns  2    
 distance("pick", "walk")    returns  3
 distance("zzzz", "walk")    returns  4
 

Parameters:

s - a non-null string

t - a non-null string

Returns:

the number of characters that differ between s and t

Precondition:

s.length() == t.length()

mostFrequentChar

public static char mostFrequentChar(String s)

Returns the character that appears most frequently in the string s. You may assume that only one character appears most frequently in s.

Parameters:

s - a string

Returns:

the character that appears most frequently in the string s

Precondition:

s.length() is at least 1