1. String class  Construct a string  String str = new String(“welcome”);  Char[] charr = {‘G’, ‘o’, ‘o’, ‘d’};  String mes = new String(charr);  A full list of String class methods and constructors P259 Chapter 7.2

2. Some String methods int length() String subString( int beginindex) String toLowerCase() String concat( String ) char chatAt( ont index) boolean equals( String anotherString)

3. continue String concatenation  String s3 = s1.concat(s2);  S3 = s1 + s2;  S3 = message + “and “+ “HTML”; Extracting substring  String message = “Welcome to Java”.subString(1,11) + “HTML”;

4. continued String comparisons  If( string1 == string2)  Will check if string1 and string 2 refer to same object  To find out whether two string objects have same content, use equals()  If( string1.equals(string2))  S1.compareTo(s2) return 0 if s1 is equals to s2, less than 0 if s1 is lexicographically less than s2, and greater than 0 if s1 is lexicographically greater than s2  Can be used in sorting algorithm

5. Finding a character in a string int indexOf( int ch) “welcome to Java”.indexOf(‘w’) returns 0 “welcome to Java”.indexOf(“come”) return 3 lastIndexOf return the index of the character last time appear in string

6. Converting characters and numeric values to strings The valueOf method can be used to convert an array of characters into a string. There are several overloaded versions of the valueOf method that can be used to convert a character and numeric values to strings with different parameter type For example, to convert a double value 5.44 to a string, String.valueOf(5.44)

7. Character class Java provide a wrapper class for every data type. Character for char You can create a Character object from a char value Character ch = new Character(‘a’); charValue() method return the character value wrapped in the Character object. See page 268 Chapter 7.3 for the full list of methods in Character class