The document discusses user-defined methods in Java programming. It covers key concepts like value-returning and void methods, parameters, and scope. It provides examples of defining methods that return values or perform actions, and using reference variables and primitive data types as parameters. The document also explains how parameters are passed by value for primitive types but by reference for objects, and the scope rules for identifiers within methods and classes.

1. Java Programming: From Problem Analysis to Program Design, 3e Chapter 7 User-Defined Methods

5. Predefined Classes (continued) Java Programming: From Problem Analysis to Program Design, 3e

6. Java Programming: From Problem Analysis to Program Design, 3e Predefined Classes (continued)

7. Java Programming: From Problem Analysis to Program Design, 3e Predefined Classes (continued)

8. Java Programming: From Problem Analysis to Program Design, 3e Predefined Classes (continued)

9. class Character (Package: java.lang ) Java Programming: From Problem Analysis to Program Design, 3e

10. Java Programming: From Problem Analysis to Program Design, 3e class Character (Package: java.lang ) (continued)

11. Java Programming: From Problem Analysis to Program Design, 3e class Character (Package: java.lang ) (continued)

12. Syntax: Value-Returning Method Java Programming: From Problem Analysis to Program Design, 3e

16. Equivalent Method Definitions Java Programming: From Problem Analysis to Program Design, 3e public static double larger( double x, double y) { double max; if (x >= y) max = x; else max = y; return max; }

20. Solution: isPalindrome Method Java Programming: From Problem Analysis to Program Design, 3e public static boolean isPalindrome(String str) { int len = str.length(); int i, j; j = len - 1; for (i = 0; i <= (len - 1) / 2; i++) { if (str.charAt(i) != str.charAt(j)) return false ; j--; } return true ; }

21. Sample Runs: Palindrome Number Java Programming: From Problem Analysis to Program Design, 3e

22. Sample Runs: Palindrome Number (continued) Java Programming: From Problem Analysis to Program Design, 3e

25. Solution: Largest Number Java Programming: From Problem Analysis to Program Design, 3e static Scanner console = new Scanner(System.in); public static void main(String[] args) { double num; double max; int count; System.out.println(&quot;Enter 10 numbers.&quot;); num = console.nextDouble(); max = num; for (count = 1; count < 10; count++) { num = console.nextDouble(); max = larger(max, num); } System.out.println(&quot;The largest number is &quot; + max); }

29. Void Methods with Parameters: Syntax Java Programming: From Problem Analysis to Program Design, 3e

30. Void Methods with Parameters: Syntax (continued) Java Programming: From Problem Analysis to Program Design, 3e

34. Reference Variables as Parameters: type String Java Programming: From Problem Analysis to Program Design, 3e

35. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e Example 7-11 public class Example7_11 { public static void main(String[] args) { int num1; //Line 1 IntClass num2 = new IntClass(); //Line 2 char ch; //Line 3 StringBuffer str; //Line 4 num1 = 10; //Line 5 num2.setNum(15); //Line 6 ch = 'A'; //Line 7 str = new StringBuffer(&quot;Sunny&quot;); //Line 8 System.out.println(&quot;Line 9: Inside main: &quot; + &quot;num1 = &quot; + num1 + &quot;, num2 = &quot; + num2.getNum() + &quot;, ch = &quot; + ch + &quot;, and str = &quot; + str); //Line 9

36. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e funcOne(num1, num2, ch, str); //Line 10 System.out.println(&quot;Line 11: After funcOne: &quot; + &quot;num1 = &quot; + num1 + &quot;, num2 = &quot; + num2.getNum() + &quot;, ch = &quot; + ch + &quot;, and str = &quot; + str); //Line 11 }

37. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e public static void funcOne( int a, IntClass b, char v, StringBuffer pStr) { int num; //Line 12 int len; //Line 13 num = b.getNum(); //Line 14 a++; //Line 15 b.addToNum(12); //Line 16 v = 'B'; //Line 17 len = pStr.length(); //Line 18 pStr.delete(0, len); //Line 19 pStr.append(&quot;Warm&quot;); //Line 20 System.out.println(&quot;Line 21: Inside funcOne: &quot; + &quot; a = &quot; + a + &quot;, b = &quot; + b.getNum() + &quot;, v = &quot; + v + &quot;, pStr = &quot; + pStr + &quot;, len = &quot; + len + &quot;, and num = &quot; + num); //Line 21 } }

38. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e

39. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e num1 = 10; //Line 5 num2.setNum(15); //Line 6 ch = 'A'; //Line 7 str = new StringBuffer(&quot;Sunny&quot;); //Line 8

40. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e System.out.println(&quot;Line 9: Inside main: &quot; + &quot;num1 = &quot; + num1 + &quot;, num2 = &quot; + num2.getNum() + &quot;, ch = &quot; + ch + &quot;, and str = &quot; + str); //Line 9

41. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e int num; //Line 12 int len; //Line 13 num = b.getNum(); //Line 14

42. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e num = b.getNum(); //Line 14

43. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e a++; //Line 15

44. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e b.addToNum(12); //Line 16

45. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e v = 'B'; //Line 17

46. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e len = pStr.length(); //Line 18

47. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e pStr.delete(0, len); //Line 19

48. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e pStr.append(&quot;Warm&quot;); //Line 20

49. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e System.out.println(&quot;Line 21: Inside funcOne: &quot; + &quot; a = &quot; + a + &quot;, b = &quot; + b.getNum() + &quot;, v = &quot; + v + &quot;, pStr = &quot; + pStr + &quot;, len = &quot; + len + &quot;, and num = &quot; + num); //Line 21

50. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e

51. Reference Variables as Parameters: type String (continued) Java Programming: From Problem Analysis to Program Design, 3e System.out.println(&quot;Line 11: After funcOne: &quot; + &quot;num1 = &quot; + num1 + &quot;, num2 = &quot; + num2.getNum() + &quot;, ch = &quot; + ch + &quot;, and str = &quot; + str); //Line 11

60. Scope Rules: Demonstrated Java Programming: From Problem Analysis to Program Design, 3e

61. Scope Rules: Demonstrated (continued) Java Programming: From Problem Analysis to Program Design, 3e

70. Java Programming: From Problem Analysis to Program Design, 3e Programming Example: Data Comparison (continued)