JK now I actually fixed error for div by 0

Console.java

@@ -59,6 +59,7 @@ public class Console {
                     //error message when trying to divide by 0.
                     if (basicInput2 == 0) {
                         Console.println("undefined");
+                        basicAnswer = Double.NaN;
                         //Insert return to main menu.
                     } else {
                         basicAnswer = basicCalc.getQuotient(basicInput1, basicInput2);
@@ -72,9 +73,9 @@ public class Console {
                     basicAnswer = Double.NaN;
                     Console.println("Invalid Input");
                 }
-                if (!basicMode.equals("4") && !(basicInput2 == 0)) {
+                
                 Console.println(Double.toString(basicAnswer));
-            }
+            
                 break;
                 case "2":
                 advCalc.realAdvanced();