working on account

src/main/java/rocks/zipcode/quiz5/fundamentals/StringUtils.java

@@ -63,11 +63,14 @@ public class StringUtils {
         return str2;
     }
 
-    public static String invertCasing(String str) {
-
-        for (int i = 0; i <str.length() ; i++) {
-         //   if (str.charAt(i))
+    public static String invertCasing(String text) {
+        StringBuilder textSB = new StringBuilder(text);
+        for(int i = 0; i < text.length(); i++) {
+            if(text.charAt(i) > 64 && text.charAt(i) < 91)
+                textSB.setCharAt(i, (char)(text.charAt(i) + 32));
+            else if(text.charAt(i) > 96 && text.charAt(i) < 123)
+                textSB.setCharAt(i, (char)(text.charAt(i) - 32));
         }
-        return null;
+        return textSB.toString();
     }
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/account/Account.java

@@ -3,11 +3,26 @@ package rocks.zipcode.quiz5.objectorientation.account;
 /**
  * @author leon on 30/12/2018.
  */
-public class Account extends BankAccount {
+public class Account extends BankAccount implements Transactable {
     public Long getId() {
         return null;
     }
 
     public void setId(Long id) {
     }
+
+    @Override
+    public void deposit(Double amountToIncreaseBy) {
+
+    }
+
+    @Override
+    public void withdrawal(Double amountToDecreaseBy) {
+
+    }
+
+    @Override
+    public Double getBalance() {
+        return null;
+    }
 }