Question

A class CalSeries has been defined to calculate the sum of the series:

sum = 1 + x + x² + x³ ..... + xⁿ

Some of the members of the class are given below:

Class name:	CalSeries
Data members/instance variables:
x:	integer to store the value of x
n:	integer to store the value of n
sum:	integer to store sum of the series
Member functions/methods:
CalSeries( ):	default constructor
void input( ):	to accept the values of x and n
int power( int p,int q):	return the power of p raised to q (pq) using recursive technique
void cal( ):	calculates the sum of the series by invoking the method power() and displays the result with an appropriate message

Specify the class CalSeries, giving details of the constructor, void input(), int power(int, int) and void call( ). Define the main() function to create an object and call the member function accordingly to enable the task.

Answer 1

import java.util*;
public class CalSeries
{
    int x,n,sum;
    public CalSeries()
    {
      x=0;
      n=0;
      sum=1;
    }
    public void input()
    {
      Scanner in = new Scanner(System.in);
      System.out.println(“Enter the value of x”);
      x=innextInt();
      System.out.println(“Enter the value of n");
      n=in.nextInt();
    }
    public int power(int p,int q)
    {
      if (q==1)
        return x;
      else return x*power(x,q-1);
    }
    public void cal()
    {
      for(int i=1;i<=n;i++)
      {
        int r=power(x,i);
        sum+=r;
    }
    System.out.println(“Sum of the series is :"+
    sum);
  }
  public static void main(String args[])
  {
    CalSeries obj=new CalSeries();
    obj.input();
    obj.cal();
  }
}