Question

US government website says the following interesting information: In 2017, the average annual electricity consumption for a U.S. residential utility customer was 10,399 kilowatthours (kWh), an average of 867 kWh per month. Louisiana had the highest annual electricity consumption at 14,242 kWh per residential customer, and Hawaii had the lowest at 6,074 kWh per residential customer.

Let us compute the electricity usage and the bill for last month by asking a few questions to a homeowner. Here are the input parameters and output format.

Input: 
# of light bulbs 
Average # of hours each bulb is ON in a day 
AC unit's power 
Typical # of hours AC unit is ON in a day 
# of FANs 
Average # of hours each Fan is ON in a day 
Per-unit price of electricity 

Formatted output: 
Total electricity usage: NNNN kWh 
Bulbs: XX.X% AC: YY.Y% FANs: ZZ.Z% 
Electricity bill for the month: $ NNNN.NN

Here is the sample input:

# of light bulbs: 10

Average # of hours each bulb is ON in a day: 2.4

AC unit's power: 900

Typical # of hours AC unit is ON in a day: 10.5

# of FANs: 4

Average # of hours each Fan is ON in a day: 8.5

Per-unit price of electricity: 9.5

Here is the corresponding output:

Total electricity usage: 368 kWh 
Bulbs: 11.8% AC: 77.1% FANs: 11.1% 
Electricity bill for the month: $ 34.91

Notes:

• Assume that each bulb consumes 60W and each fan consumes 40W.
• Assume that the home has only one AC unit and all other appliances including cooking range use other energy sources, NOT electricity. AC unit power is specified in watts.
• 1 kWh stands for 1000 Watt-hours and it is considered as 1 unit of Electricity and the per-unit price is specified in cents.
• Assume that the last month had 30 days.

Answer 1

C++ Program:

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
int numBulbs, numFans;
double avgBulbON, ACUnitPower, AC_ON_Hrs, avgFanON, perUnitPrice;
double fanC, bulbC, AC_C, totalConsumption=0;
double bill;

//Reading input from user
cout << "\n# of light bulbs: ";
cin >> numBulbs;

cout << "Average # of hours each bulb is ON in a day: ";
cin >> avgBulbON;

cout << "AC unit's power: ";
cin >> ACUnitPower;

cout << "Typical # of hours AC unit is ON in a day: ";
cin >> AC_ON_Hrs;

cout << "# of FANs: ";
cin >> numFans;

cout << "Average # of hours each Fan is ON in a day: ";
cin >> avgFanON;

cout << "Per-unit price of electricity: ";
cin >> perUnitPrice;

//Processing output
bulbC = (numBulbs * avgBulbON * 60 * 30) / 1000;
fanC = (numFans * avgFanON * 40 * 30) / 1000;
AC_C = (900 * 10.5 * 30) / 1000;

//Calculating total consumption
totalConsumption = bulbC + fanC + AC_C;

//Calculating Bill
bill = totalConsumption * (perUnitPrice * 0.01);

cout << fixed << setprecision(0);
cout << "\n\nTotal electricity usage: " << totalConsumption << " kWh";
cout << fixed << setprecision(1);
cout << "\nBulbs: " << ((bulbC/totalConsumption)*100) << "% AC: " << ((AC_C/totalConsumption)*100) << "% FANs: " << ((fanC/totalConsumption)*100) << "% ";
cout << fixed << setprecision(2);
cout << "\nElectricity bill for the month: $ " << bill << "\n\n";

return 0;
}

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Sample Run:

CATCIUSElectricity bin\Debug\USElectricity.exe of light bulbs: 10 Average of hours each bulb is ON in a day: 2.4 AC unit's power: 900 Typical of hours AC unit is ON in a day: 10.5 # of FANS: 4 Average #of hours each Fan is ON in a day: 8.5 Per-unit price of electricity: 9.5 Total electricity usage: 368 kWh Bulbs: 11.8% AC: 77.1% FANS: 11.1% Electricity bill for the month: $ 34.91 Process returned 0 (0x0) Press any key to continue. execution time : 14.162 s