Question

Consider the following classes (For Java):

class A {
public void process() {
// Details omitted
}
}

class B extends A {
public void compute() {
// Details omitted
}
}

class C extends B {
public void calculate() {
// Details omitted
}
}

Which of the following client code fragments are legal?

Select one or more:

C c = new C();
c.compute();

A c = new C();
c.process();

C c = new A();
c.process();

A a = new A();
a.process();

B b = new B();
b.process();

B b = new B();
b.compute();

A c = new A();
c.calculate();

C c = new C();
c.process();

Answer 1

The following are legal

C c = new C();
c.compute();
-------
A c = new C();
c.process();
-------
A a = new A();
a.process();
-------
B b = new B();
b.process();
----
B b = new B();
b.compute();
-----
C c = new C();
c.process();

We can assign derived class objects to super class variables but not vice versa. Also methods in super class are available in derived classes