Program to calculate the bill in c++

#include <iostream>
using namespace std;

// Function to calculate the bill using pass-by-value
double calculateBillByValue(double price, int quantity) {
    double bill = price * quantity;
    return bill;
}

// Function to calculate the bill using pass-by-reference
void calculateBillByReference(double price, int quantity, double &bill) {
    bill = price * quantity;
}

int main() {
    double price;
    int quantity;
    double billValue = 0.0, billReference = 0.0;

    // Input price and quantity
    cout << "Enter the price of the item: ";
    cin >> price;
    cout << "Enter the quantity: ";
    cin >> quantity;

    // Calculate bill using pass-by-value
    billValue = calculateBillByValue(price, quantity);
    cout << "Bill calculated using pass-by-value: $" << billValue << endl;

    // Calculate bill using pass-by-reference
    calculateBillByReference(price, quantity, billReference);
    cout << "Bill calculated using pass-by-reference: $" << billReference << endl;

    return 0;
}

#include <iostream>

using namespace std;

// Function to calculate the bill using pass-by-value

double calculateBillByValue(double price, int quantity) {

double bill = price * quantity;

return bill;

}

// Function to calculate the bill using pass-by-reference

void calculateBillByReference(double price, int quantity, double &bill) {

bill = price * quantity;

}

int main() {

double price;

int quantity;

double billValue = 0.0, billReference = 0.0;

// Input price and quantity

cout << "Enter the price of the item: ";

cin >> price;

cout << "Enter the quantity: ";

cin >> quantity;

// Calculate bill using pass-by-value

billValue = calculateBillByValue(price, quantity);

cout << "Bill calculated using pass-by-value: $" << billValue << endl;

// Calculate bill using pass-by-reference

calculateBillByReference(price, quantity, billReference);

cout << "Bill calculated using pass-by-reference: $" << billReference << endl;

return 0;

}

Explanation:

Pass-by-Value (calculateBillByValue):
- Function Definition: double calculateBillByValue(double price, int quantity)
- This function receives the price and quantity as copies of the original values.
- It calculates the bill by multiplying price and quantity.
- The result is returned to the calling function, but the original variables in main remain unchanged.
Pass-by-Reference (calculateBillByReference):
- Function Definition: void calculateBillByReference(double price, int quantity, double &bill)
- This function also receives price and quantity, but in addition, it receives a reference to the variable bill.
- It calculates the bill by multiplying price and quantity and stores the result directly in the bill variable, which is passed by reference.
- The original billReference variable in main is modified.
Main Function (main):
- The program prompts the user to enter the price of an item and the quantity.
- It then calculates the bill using both the pass-by-value and pass-by-reference methods.
- Finally, it displays the calculated bills.

Example Outputs:

Example 1:

Input:

Price: 20
Quantity: 5

Output:

Enter the price of the item: 20
Enter the quantity: 5
Bill calculated using pass-by-value: $100
Bill calculated using pass-by-reference: $100

Enter the price of the item: 20

Enter the quantity: 5

Bill calculated using pass-by-value: $100

Bill calculated using pass-by-reference: $100

Example 2:

Input:

Price: 15.5
Quantity: 3

Output:

Enter the price of the item: 15.5
Enter the quantity: 3
Bill calculated using pass-by-value: $46.5
Bill calculated using pass-by-reference: $46.5
Enter the price of the item: 15.5
Enter the quantity: 3
Bill calculated using pass-by-value: $46.5
Bill calculated using pass-by-reference: $46.5

Enter the price of the item: 15.5

Enter the quantity: 3

Bill calculated using pass-by-value: $46.5

Bill calculated using pass-by-reference: $46.5