Fix Account exception handling problem

- Consolidate into 1 class called Account.java
- Clarify instructions and post instructions in the file
- Close Scanner object when done

Author: phrdang

src/com/codefortomorrow/advanced/chapter14/practice/Account.java

@@ -0,0 +1,58 @@
+package com.codefortomorrow.advanced.chapter14.practice;
+
+/*
+Create the following classes that simply extend the `Exception` class: 
+
+- `InvalidUsernameException`
+- `InvalidPasswordException`
+- `InvalidAgeException`
+- `PasswordMismatchException`
+
+In the `Account` class, code a method called `createAccount` that takes a `username`, `age`,
+`password`, and `confirmPassword` as parameters. 
+
+In `createAccount`, throw an:
+
+- `InvalidUsernameException` - if the given username is <4 or >10 characters.
+- `InvalidPasswordException` - if the given password is <4 or >10 characters.
+- `InvalidAgeException` - if the given age is <18.
+- `PasswordMismatchException` - if the given password does not match the given confirm password.
+
+In your `main` method (within the `Account` class):
+
+- To simulate the creation of an account online, prompt the user to enter their username, age,
+  password, and their password again (to confirm).
+- Call the `createAccount` method continuously with the user's input and use `try`/`catch` to
+  handle the possible exceptions and print the appropriate error message. (You can assume that
+  the user input will only throw at most 1 exception.)
+- Keep asking the user for input until the account is created successfully.
+
+Example output:
+
+```
+Welcome to Account Creation!
+Enter username (4 to 10 characters): hi
+Enter age: 18
+Enter password (4 to 10 characters): thisislong
+Confirm password (4 to 10 characters): thisislong
+Invalid username.
+Enter username (4 to 10 characters): four
+Enter age: 18
+Enter password (4 to 10 characters): thisislong
+Confirm password (4 to 10 characters): thisislong
+Account created successfully!
+```
+*/
+
+public class Account {
+
+    public static void main(String[] args) {
+        // Write your code here
+    }
+
+    public static void createAccount(String username, int age, String password, String confirmPassword) {
+        // Write your code here
+    }
+}
+
+// Write exception classes here

src/com/codefortomorrow/advanced/chapter14/practice/account/InvalidAgeException.java

@@ -0,0 +1,110 @@
+package com.codefortomorrow.advanced.chapter14.solutions;
+
+import java.util.Scanner;
+
+/*
+Create the following classes that simply extend the `Exception` class: 
+
+- `InvalidUsernameException`
+- `InvalidPasswordException`
+- `InvalidAgeException`
+- `PasswordMismatchException`
+
+In the `Account` class, code a method called `createAccount` that takes a `username`, `age`,
+`password`, and `confirmPassword` as parameters. 
+
+In `createAccount`, throw an:
+
+- `InvalidUsernameException` - if the given username is <4 or >10 characters.
+- `InvalidPasswordException` - if the given password is <4 or >10 characters.
+- `InvalidAgeException` - if the given age is <18.
+- `PasswordMismatchException` - if the given password does not match the given confirm password.
+
+In your `main` method (within the `Account` class):
+
+- To simulate the creation of an account online, prompt the user to enter their username, age,
+  password, and their password again (to confirm).
+- Call the `createAccount` method continuously with the user's input and use `try`/`catch` to
+  handle the possible exceptions and print the appropriate error message. (You can assume that
+  the user input will only throw at most 1 exception.)
+- Keep asking the user for input until the account is created successfully.
+
+Example output:
+
+```
+Welcome to Account Creation!
+Enter username (4 to 10 characters): hi
+Enter age: 18
+Enter password (4 to 10 characters): thisislong
+Confirm password (4 to 10 characters): thisislong
+Invalid username.
+Enter username (4 to 10 characters): four
+Enter age: 18
+Enter password (4 to 10 characters): thisislong
+Confirm password (4 to 10 characters): thisislong
+Account created successfully!
+```
+*/
+
+public class Account {
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        System.out.println("Welcome to Account Creation!");
+        while (true) {
+            System.out.print("Enter username (4 to 10 characters): ");
+            String username = sc.next();
+            System.out.print("Enter age: ");
+            int age = sc.nextInt();
+            System.out.print("Enter password (4 to 10 characters): ");
+            String password = sc.next();
+            System.out.print("Confirm password (4 to 10 characters): ");
+            String confirmPassword = sc.next();
+
+            try {
+                createAccount(username, age, password, confirmPassword);
+                System.out.println("Account created successfully!");
+                sc.close();
+                break;
+            } catch (InvalidUsernameException e) {
+                System.out.println("Invalid username.");
+            } catch (InvalidPasswordException e) {
+                System.out.println("Invalid password.");
+            } catch (InvalidAgeException e) {
+                System.out.println("Must be 18 or older to create an account.");
+            } catch (PasswordMismatchException e) {
+                System.out.println("Passwords don't match!");
+            }
+        }
+    }
+
+    public static void createAccount(
+        String username,
+        int age,
+        String password,
+        String confirmPassword
+    )
+        throws InvalidAgeException, InvalidPasswordException, InvalidUsernameException, PasswordMismatchException {
+        if (username.length() < 4 || username.length() > 10) {
+            throw new InvalidUsernameException();
+        }
+
+        if (age < 18) {
+            throw new InvalidAgeException();
+        }
+
+        if (password.length() < 4 || password.length() > 10) {
+            throw new InvalidPasswordException();
+        }
+        
+        if (!password.equals(confirmPassword)) {
+            throw new PasswordMismatchException();
+        }
+    }
+}
+
+class InvalidUsernameException extends Exception {}
+class InvalidPasswordException extends Exception {}
+class InvalidAgeException extends Exception {}
+class PasswordMismatchException extends Exception {}