A superclass **Number** is defined to calculate the factorial of a number. Define a subclass **Series** to find the sum of the series S = 1! + 2! + 3! + 4! + … + n!

The details of the members of both the classes are given below:

**Class name:** Number**Data members/instance variables:**

n: to store an integer number.**Member functions/methods:**

Number(int num): parameterized constructor to initialize the data member n = num.

int factorial(int a): returns the factorial of a number (factorial of n = 1 × 2 × 3 × … × n).

void display(): displays the data member

**Class name:** Series**Data members/instance variables:**

sum: to store the sum of the series.**Member functions/methods:**

Series(…): parameterized constructor to initialize the data members of both the classes.

void calSum(): calculates the sum of the given series.

void display(): displays the data members of both the classes.

*Assume that the superclass Number has been defined.* Using the concept of inheritance, specify the class Series giving details of the constructor, void calSum() and void display().

**The superclass, main function and algorithm need not be written.**

```
class Series extends Number{
int sum;
public Series(int num){
super(num);
sum = 0;
}
public void calSum(){
for(int i = 1; i <= n; i++)
sum += factorial(i);
}
public void display(){
super.display();
System.out.println("Sum = " + sum);
}
}
```