Set a default price when you add a product

src/ProductAdder.js

@@ -3,10 +3,10 @@ import { Form, InputGroup, Col, Row, Button } from "react-bootstrap";
 
 function ProductAdder(props) {
   const [code, setCode] = useState();
-  const [name, setName] = useState();
-  const [eur, setEur] = useState();
-  const [cents, setCents] = useState();
-  const [stock, setStock] = useState();
+  const [name, setName] = useState("");
+  const [eur, setEur] = useState(0);
+  const [cents, setCents] = useState(0);
+  const [stock, setStock] = useState(0);
 
   const add = (e) => {
     e.preventDefault();