Strings, Characters and Regular Expressions - Java: How to Program Early Objects - page 600

19
20 for ( int count = s1.length() - 1 ; count >= 0 ; count--)

21 System.out.printf( "%c " , s1.charAt(count) );

22
23

// copy characters from string into charArray

24

s1.getChars( 0 , 5 , charArray, 0 );

25

System.out.printf( "%nThe character array is: " );

26
27

for ( char character : charArray)

28

System.out.print(character);

29
30

System.out.println();

31

}

32

} // end class StringMiscellaneous

s1: hello there
Length of s1: 11
The string reversed is: e r e h t o l l e h
The character array is: hello

Fig. 14.2 | String methods length , charAt and getChars . (Part 2 of 2.)

Line 15 uses String method length to determine the number of characters in String
s1 . Like arrays, strings know their own length. However, unlike arrays, you access a
String 's length via class String 's length method.
Lines 20-21 print the characters of the String s1 in reverse order (and separated by
spaces). String method charAt (line 21) returns the character at a specific position in the
String . Method charAt receives an integer argument that's used as the index and returns
the character at that position. Like arrays, the first element of a String is at position 0.
Line 24 uses String method getChars to copy the characters of a String into a char-
acter array. The first argument is the starting index from which characters are to be copied.
The second argument is the index that's one past the last character to be copied from the
String . The third argument is the character array into which the characters are to be
copied. The last argument is the starting index where the copied characters are placed in
the target character array. Next, lines 27-28 print the char array contents one character at
a time.

14.3.3 Comparing Strings
Chapter 19 discusses sorting and searching arrays. Frequently, the information being sort-
ed or searched consists of String s that must be compared to place them into order or to
determine whether a string appears in an array (or other collection). Class String provides
methods for comparing strings, as demonstrated in the next two examples.
To understand what it means for one string to be greater than or less than another,
consider the process of alphabetizing a series of last names. No doubt, you'd place “Jones”
before “Smith” because the first letter of “Jones” comes before the first letter of “Smith”
in the alphabet. But the alphabet is more than just a list of 26 letters—it's an ordered list
of characters. Each letter occurs in a specific position within the list. Z is more than just a
letter of the alphabet—it's specifically the twenty-sixth letter of the alphabet.