java Switch default for the rest of indexes not used in the cases

I need to use the Switch's default to assign values to the array elements with indexes that were not used in the Cases.

Example:

public class sample {

public static void main(String[] args) {



    String[] animalArray = new String[5];



    String animal = "Dog";



    switch(animal){             

    case "Dog":

        //The position 0 is found using some calculation

        animalArray[0] = "Dog"; 

        break;



    case "Cat": 

        ////The position 3 is found using some calculation

        animalArray[3] = "Cat";

        break;      

    default:



        //How do I get the value of x to be 1,2,4



        animalArray[x] = "Undefined";

    }           

    }    

}

Now I need some way to tell that the indexes that were not already used in the case statement should be used here in the default.

How do I implement that?