@@ -0,0 +1,186 @@
+%0Apackage innovimax.mixthem.operation;%0Aimport innovimax.mixthem.MixException;%0A%0Apublic interface ICharOperation extends IOperation %7B%0A%09String process(int c1, int c2) throws MixException;%0A%7D%0A

Create ICharOperation.java