ICS3U – StringBuffer

1. ICS3U – StringBuffer Teacher: Mr. Ho Course URL: http://computerNHSS.wikispaces.com

2. Review of String • String is a special data type (or class) in Java • E.g. String str1 = “Hello, I am a string”; • Once str1 is assigned a value, its value cannot be changed.

3. StringBuffer • Another special data type (or class) in Java • Like String, except that the value of StringBuffer can be changed.

4. Built-In Methods • StringBuffer sb = new StringBuffer(“Hello”); • sb.length(); // length of StringBuffer • sb.charAt(1); // getting a character • sb.insert(2, “ABC”); // inserting • sb.append(“DEF”); // appending • sb.reverse(); // reversing StringBuffer • String s = sb.toString(); // getting String

5. sb.length() In the main() method: StringBuffer sb = new StringBuffer(“Hello”); System.out.println(sb.length()); Output: 5

6. sb.charAt(1) In the main() method: StringBuffer sb = new StringBuffer(“Hello”); System.out.println(sb.charAt(1)); Output: e

7. sb.insert(2, “ABC”) In the main() method: StringBuffer sb = new StringBuffer(“Hello”); System.out.println(sb.insert(2, “ABC”)); Output: HeABCllo

8. sb.append(“DEF”) In the main() method: StringBuffer sb = new StringBuffer(“Hello”); System.out.println(sb.append(“DEF”)); Output: HelloDEF

9. sb.reverse() In the main() method: StringBuffer sb = new StringBuffer(“Hello”); System.out.println(sb.reverse()); Output: olleH

10. sb.toString() In the main() method: StringBuffer sb = new StringBuffer(“Hello”); String s = sb.toString(); System.out.println(s); Output: Hello

11. Classwork • Go to http://computerNHSS.wikispaces.com • Download the classwork: • JBB_pg_18.pdf • JBB_pg_19.pdf • JBB_pg_22.pdf