1. Handle Exceptions

2. Murach’s Java SE 6, C5© 2007, Mike Murach & Associates, Inc. Slide 2 What is an Exception?

3. Murach’s Java SE 6, C5© 2007, Mike Murach & Associates, Inc. Slide 3 Scanner class’ next methods may throw inputMitsmatchException if the data entered is not the expected data type. For example, nextDouble method gets text data.

4. Example of Exception Exception in thread "main" java.util.InputMismatchException at java.util.Scanner.throwFor(Scanner.java:840) at java.util.Scanner.next(Scanner.java:1461) at java.util.Scanner.nextDouble(Scanner.java:2387) at testinstall.Main.main(Main.java:26) Java Result: 1 BUILD SUCCESSFUL (total time: 10 seconds)

5. Murach’s Java SE 6, C5© 2007, Mike Murach & Associates, Inc. Slide 5 Using Try / Catch Statements to Handle Exceptions

6. Try Catch: Typically work with a loop structure Scanner sc=new Scanner(System.in); try{ System.out.println("enter loan:"); double loan=sc.nextDouble(); System.out.println("enter rate in %:"); double rate=sc.nextDouble(); System.out.println("enter term in year:"); double term=sc.nextDouble(); double monPayment=(loan*rate/100/12)/(1-(Math.pow(1+rate/100/12,-12*term))); System.out.println("Monthly payment is: =" + monPayment); } catch (InputMismatchException e) { sc.next(); System.out.println("Enter numeric data only"); } System.out.println("Thank you for using payment calculator!");

7. Loan Calculator with Exception Handling Scanner sc=new Scanner(System.in); String flag="Y"; while (flag.equalsIgnoreCase("Y")){ try{ System.out.println("enter loan:"); double loan=sc.nextDouble(); System.out.println("enter rate in %:"); double rate=sc.nextDouble(); System.out.println("enter term in year:"); double term=sc.nextDouble(); double monPayment=(loan*rate/100/12)/(1-(Math.pow(1+rate/100/12,-12*term))); System.out.println("Monthly payment is: =" + monPayment); System.out.println("Do you want to continue? (Y/N):"); flag=sc.next(); } catch (InputMismatchException e) { sc.next(); System.out.println("Enter numeric data only"); continue; } System.out.println("Thank you for using payment calculator!");

8. Methods of Exception Class catch (InputMismatchException e) catch (Exception e) – Catch any exceptions System.out.println(e.getMessage()); System.out.println(e.getStackTrace());

9. String Class Methods toLowerCase() toUpperCase() substring(int beginIndex) – "unhappy".substring(2) returns "happy" – 0-based index substring(int beginIndex, int endIndex) – "hamburger".substring(4, 8) returns "urge" "smiles".substring(1, 5) returns "mile" length() indexOf( char)

10. Full name format: First Name + Space + Last Name Change the Full Name to proper format where the first letter of First Name and Last Name changed to uppercase and other letters in lower case Example: “david chao” -> “David Chao”

11. Code Example public static void main(String[] args) { // TODO code application logic here Scanner sc=new Scanner(System.in); System.out.println("enter full name:"); String FullName=sc.nextLine(); int spaceIndex = FullName.indexOf(" "); String firstName=FullName.substring(0,spaceIndex); String lastName=FullName.substring(spaceIndex+1); String newFullName=proper(firstName) + " " + proper(lastName); System.out.println("Proepr full name:" + newFullName); } public static String proper(String Name){ return Name.substring(0,1).toUpperCase()+ Name.substring(1).toLowerCase(); }