hacks update

_notebooks/Foundation/2023-09-21-hacks.ipynb

@@ -80,17 +80,124 @@
   {
    "cell_type": "markdown",
    "metadata": {},
-   "source": []
+   "source": [
+    "## Multiple Choice\n",
+    "### 1. What is wrong with this block of code?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "vscode": {
+     "languageId": "java"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class Shape{\n",
+    "    double length = 0;\n",
+    "    double width = 0;\n",
+    "    \n",
+    "    public Shape(double length, double width){\n",
+    "        this.length = length;\n",
+    "        this.width = width;\n",
+    "    }\n",
+    "\n",
+    "    public double getArea(){\n",
+    "        return this.length * this.width;\n",
+    "    }\n",
+    "\n",
+    "    private String toString(){\n",
+    "        return \"Shape length:\"+ (new Double(this.length)).toString() + \" width:\" + (new Double(this.width)).toString();\n",
+    "    }\n",
+    "}\n",
+    "\n",
+    "Shape myShape = new Shape(2,3);\n",
+    "\n",
+    "System.out.println(myShape.getArea());"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "a) You can't use the **this** keyword in the constructor\n",
+    "\n",
+    "b) When passing a **double** through an argument it must be in the form of 0.0\n",
+    "\n",
+    "c) The **toString()** method must be public\n",
+    "\n",
+    "d) The **getArea()** method doesn't return a double\n",
+    "\n",
+    "### 2. Which method cannot be exectuted in the following example of Polymorphism"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "vscode": {
+     "languageId": "java"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class Water{\n",
+    "    public String toString(){\n",
+    "        return \"Water\";\n",
+    "    }\n",
+    "\n",
+    "    private boolean isSalty(){\n",
+    "        return false;\n",
+    "    }\n",
+    "\n",
+    "    public String typeOfWater(){\n",
+    "        return \"Static\";\n",
+    "    }\n",
+    "\n",
+    "}\n",
+    "\n",
+    "class Lake extends Water{\n",
+    "    public String toString(){\n",
+    "        return \"Lake\";\n",
+    "    }\n",
+    "\n",
+    "    public boolean isSalty(){\n",
+    "        return true;\n",
+    "    }\n",
+    "}\n",
+    "\n",
+    "Water myLakeWater = new Lake();"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "a) **typeOfWater()**\n",
+    "\n",
+    "b) **isSalty()**\n",
+    "\n",
+    "c) **toString()**\n",
+    "\n",
+    "d) **getClass()**"
+   ]
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "java (IJava/j!)",
+   "display_name": "Java",
    "language": "java",
-   "name": "jbang-ijava"
+   "name": "java"
   },
   "language_info": {
-   "name": "java"
+   "codemirror_mode": "java",
+   "file_extension": ".jshell",
+   "mimetype": "text/x-java-source",
+   "name": "Java",
+   "pygments_lexer": "java",
+   "version": "17.0.12+7-Ubuntu-1ubuntu222.04"
   }
  },
  "nbformat": 4,