feat: update structure

cs2030s/labs/Lab6/Not.java

@@ -0,0 +1,25 @@
+/**
+ * Represents the Not type, a conditional which inverts the given input.
+ */
+class Not implements Cond {
+  private Cond val;
+
+  public Not(Cond val) {
+    this.val = val;
+  }
+
+  @Override
+  public boolean eval() {
+    return !this.val.eval();
+  }
+
+  @Override
+  public String toString() {
+    return "!(" + this.val + ")";
+  }
+
+  @Override
+  public Cond neg() {
+    return this.val;
+  }
+}