As I see it, the class SimpleInput is not mentioned in an import
statement, thus it should be in the default package. Do you have a file
SimpleInput.java or SimpleInput.class in the same directory as Dog.java
(the class whose source you refered to)?

If not, that's your problem: the code references a class that doesn't
exist. Ask your instructor how to get it to work.

Read the chapter in your course book that handles arrays. Then, look at
following code snippet and read the relevant parts again. Make sure you
understand what it does, and answer all "why" questions. After this you'll
know how to create and use arrays. Perfectly but for the practice.

    // Warning: this code snippet does not compile. This is intentional.

    int[] intArray; // A reference to an array of int values.

    intArray = new int[3]; // Now it actually points to an array.

    System.out.println(intArray[0]); // OK. Why?
    System.out.println(intArray[1]); // Prints 0; Why?
    System.out.println(intArray[2]);
    System.out.println(intArray[3]); // IndexOutOfBoundsException. Why?

    intArray = new int[]{1,2,3}; // Alternative array creation.
    System.out.println(intArray[0]); // Prints 1
    System.out.println(intArray[1]); // Prints 2
    System.out.println(intArray[2]); // Prints 3; Why?

    intArray = new Integer[54]; // Compiler error. Why?
    intArray = new long[3]; // Compiler error. Why?

    Integer[] integerArray = new Integer[3];
    // Why does the following not work?
    System.out.println(intArray[0].intValue()); // NullPointerException.

    // This results in a compiler error for any Java version before 1.5.0.
    // Why? (hint: autoboxing)
    integerArray = new Integer[] {1,2,3};

    integerArray = new Integer[] {
        new Integer(1),
        new Integer(2),
        new Integer(3)
    }; // Alternative difinition.
    integerArray[1] = new Integer(5);

    for (int i=0; i<integerArray.length; i++) {
        System.out.println(String.valueOf(integerArray[i]));
    }