Example: Restaurant Bill Calculator in C++

// Restaurant Bill Calculator
#include <iostream> // For input/output operations (cin, cout)
#include <iomanip>  // For output formatting (setprecision, fixed)

using namespace std;

int main() {
    // Step 1: Declare variables to store inputs and calculated values
    double baseMealCost;
    double taxRate;       // as a percentage, e.g., 7 for 7%
    double tipPercentage; // as a percentage, e.g., 15 for 15%
    double taxAmount;
    double tipAmount;
    double totalBill;

    // Step 2: Get input from the user for base meal cost
    cout << "Enter the base cost of the meal: $";
    cin >> baseMealCost;

    // Step 3: Get input for tax rate
    cout << "Enter the tax rate (e.g., 7 for 7%): ";
    cin >> taxRate;

    // Step 4: Get input for tip percentage
    cout << "Enter the tip percentage (e.g., 15 for 15%): ";
    cin >> tipPercentage;

    // Step 5: Convert percentages to decimal for calculation
    // Example: 7% becomes 0.07, 15% becomes 0.15
    double decimalTaxRate = taxRate / 100.0;
    double decimalTipPercentage = tipPercentage / 100.0;

    // Step 6: Calculate the tax amount
    taxAmount = baseMealCost * decimalTaxRate;

    // Step 7: Calculate the tip amount (usually on the meal cost + tax)
    // This program calculates tip on (base cost + tax).
    tipAmount = (baseMealCost + taxAmount) * decimalTipPercentage;

    // Step 8: Calculate the total bill
    totalBill = baseMealCost + taxAmount + tipAmount;

    // Step 9: Display the results with two decimal places for currency
    cout << fixed << setprecision(2); // Set output to fixed-point notation with 2 decimal places

    cout << "\n--- Bill Details ---" << endl;
    cout << "Base Meal Cost: $" << baseMealCost << endl;
    cout << "Tax Rate (" << taxRate << "%): $" << taxAmount << endl;
    cout << "Tip (" << tipPercentage << "%): $" << tipAmount << endl;
    cout << "--------------------" << endl;
    cout << "Total Bill:     $" << totalBill << endl;

    return 0; // Indicate successful execution
}