added error message for inverse of 0

Console.java

                     basicAnswer = Double.NaN;
                     Console.println("Invalid Input");
                 }
-                
+
                 Console.println(Double.toString(basicAnswer));
-            
+
                 break;
+
                 case "2":
                 advCalc.realAdvanced();
                 String mode = Console.getStringInput("Enter the mode: ");
                     advAnswer = advCalc.exponent(advInput1,advInput2);
 
                 }else if (mode.equals("3")){
-
+                    if (advInput1 == 0) {
+                        Console.println("undefined");
+                        advAnswer = Double.NaN;
+                    } else {
                     advAnswer = advCalc.inverse(advInput1);
-
+                }
                 }else if (mode.equals("4")){
                     advAnswer = advCalc.opposite(advInput1);