Question

Define a class Telephone having the following description:

Class name: Telephone
Data members
int prv, pre: to store the previous and present meter readings
int call: to store the calls made (i.e. pre − prv)
String name: to store name of the consumer
double amt: to store the amount
double total: to store the total amount to be paid 
Member function:
void input(): Stores the previous reading, present reading and name of the consumer
void cal(): Calculates the amount and total amount to be paid
void display(): Displays the name of the consumer, calls made, amount and total amount to be paid

Write a program to compute the monthly bill to be paid according to the given conditions and display the output as per the given format.

Calls made	Rate
Up to 100 calls	No charge
For the next 100 calls	90 paise per calls
For the next 200 calls	80 paise per calls
More than 400 calls	70 paise per calls

However, every consumer has to pay ₹ 180 per month as monthly rent for availing the service.

Output:	Name of the customer	Calls made	Amount to be paid
	...........................	...........................	...........................
	...........................	...........................	...........................

Answer 1

import java.util.*;
class Telephone
{int prv, pre, call;
String name;
double amt, total;

void input()
{Scanner in = new Scanner(System.in);
System.out.println("Enter the name of the consumer");
name = in.nextLine();
System.out.println("Enter the present meter reading");
pre = in.nextInt();
System.out.println("Enter the previous meter reading");
prv = in.nextInt();
}

void cal()
{call = pre-prv;
if (call <= 100)
amt = 0; // No charge for the first 100 calls
else if ((call > 100) && (call <= 200))
amt = 0.90 * (call - 100);
else if ((call > 200) && (call <= 400))
amt = (0.90 * 100) + 0.80 * (call - 200);
else if (call > 400)
amt = (0.90 * 100) + (0.80 * 200) + 0.70 * (call - 400);
total = 180 + amt; // monthly rent is 180
}

void display()
{System.out.println("Name of the consumer\tCalls made\tTotal amount to be paid");
System .out. println(name + " + call + "\t\t" + total);
}

public static void main(String args(])
{Telephone t = new Telephone();
t.input();
t.cal();
t.display();
}
}