Question

A programmer has to write a program for an xyz program. He has recognised that both the Div and Add values are based on the same underlying Op data structure. As a result, he has written the following JUnit test code.

@Test 
public void testDiv() {
Op aValue = new Div(8, 40, “String”); 
assertEquals(5, aValue.getVal1()); 
assertEquals(“String 40 / 8 = 5”, aValue.toString());
}

Based on this code: Write an interface for Op and write the class header for Div.

—
My response is:

public interface IDiv {
String aValue();
String toString();
}

and

public class Div (int, String) {
}

is this correct?

Answer 1

My variant is:

public interface Op {
    String getVal1();
}

and

public class Div implements Op {

    public Div(int a, int b, String c) {
        ...
    }

    public getVal1() {
        ...
    }
}

I don’t add toString() method to Op interface because each object in Java implicitly extends Object class which already has this method.