Class Program Example

An electricity board charges the following rates to domestic users to discourage large consumption of energy :

For the first 100 units − 60 P per unit

Beyond 300 units − 70 P per unit

If the total cost is more than Rs.250.00 then an additional surcharge of 25% is added to the difference. Define a class Electricity in which the function Bill computes the cost. Define a derived class More_Electricity and override Bill to add the surcharge.

Program Code:

#include<iostream>

using namespace std;

class electricity

{

protected:

float unit;

float cost;

public:

void bill()

{

cout<<"Enter the no. of units consumed : "<<endl;

cin>>unit;

if(unit <= 100)

{

cost=0.60*unit;

cout<<"Cost up to 100 unit is Rs : "<<cost;

cout<<endl;

cout<<endl;

}

else

{

if(unit>300)

{

cost=0.70*unit;

cout<<"Beyond 300 units is Rs : "<<cost;

cout<<endl;

}

}

}

};

class more_electricity : public electricity

{

float surcharge,diff,total_cost;

public:

void bill()

{

electricity :: bill();

if(cost>250.00)

{

diff = cost-250;

surcharge = diff * 0.25;

total_cost=cost+surcharge;

cout<<"Bill amount with surcharge is Rs :"<<total_cost;

cout<<endl;

}

else

{

cout<<"Bill amount is Rs :"<<cost;

cout<<endl;

}

}

};

void main()

{

more_electricity obj;

obj.bill();

return 0;

}

The program output is tested on www.jdoodle.com

Output:

Enter the no. of units consumed : 400

Beyond 300 units is Rs : 280

Bill amount with surcharge is Rs : 287.5

Thanks

Mukesh Rajput