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Thejava.lang
package contains two string classes: String and StringBuffer. You've already seen theString
class on several occasions in this tutorial. You use theString
class when you are working with strings that cannot change.StringBuffer
, on the other hand, is used when you want to manipulate the contents of the string on the fly.The
reverseIt
method in the following code uses both theString
andStringBuffer
classes to reverse the characters of a string. If you have a list of words, you can use this method in conjunction with a sort program to create a list of rhyming words (a list of words sorted by ending syllables). Just reverse all the strings in the list, sort the list, and reverse the strings again. You can see thereverseIt
method producing rhyming words in the example in How to Use Pipe Streams that shows you how to use piped streams.Thepublic class ReverseString { public static String reverseIt(String source) { int i, len = source.length(); StringBuffer dest = new StringBuffer(len); for (i = (len - 1); i >= 0; i--) dest.append(source.charAt(i)); return dest.toString(); } }reverseIt
method accepts an argument of typeString
calledsource
that contains the string data to be reversed. The method creates aStringBuffer
,dest
, the same size assource
. It then loops backwards over all the characters insource
and appends them todest
, thereby reversing the string. Finally, the method convertsdest
, aStringBuffer
, to aString
.In addition to highlighting the differences between
String
s andStringBuffer
s, this section illustrates several features of theString
andStringBuffer
classes: creatingString
s andStringBuffer
s, using accessor methods to get information about aString
orStringBuffer
, modifying aStringBuffer
, and converting one type of string to another.
This section covers these string-related topics:
Note to C and C++ Programmers: Java strings are first-class objects, unlike C and C++ strings, which are simply null-terminated arrays of 8-bit characters.
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