Example: Car Recommendation using Switch and If-Else in C++

// Car Recommendation using Switch and If-Else
#include <iostream>
#include <string>
#include <limits> // Required for numeric_limits
#include <algorithm> // Required for std::transform

int main() {
    // Step 1: Declare variables
    int budget;
    std::string fuelType;
    int seatingCapacity;

    std::cout << "Welcome to the Advanced Car Recommendation System!\n";

    // Step 2: Get user inputs with validation (similar to Approach 1)
    std::cout << "Please enter your maximum budget (in USD, e.g., 25000): ";
    while (!(std::cin >> budget) || budget <= 0) {
        std::cout << "Invalid budget. Please enter a positive number: ";
        std::cin.clear();
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
    }
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

    std::cout << "Enter desired fuel type (petrol, diesel, electric): ";
    std::getline(std::cin, fuelType);
    // Convert fuelType to lowercase for consistent comparison
    std::transform(fuelType.begin(), fuelType.end(), fuelType.begin(), ::tolower);

    std::cout << "Enter minimum seating capacity (e.g., 4, 5, 7): ";
    while (!(std::cin >> seatingCapacity) || seatingCapacity <= 0) {
        std::cout << "Invalid seating capacity. Please enter a positive number: ";
        std::cin.clear();
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
    }
    std::cout << "\n";

    // Step 3: Display user preferences
    std::cout << "Based on your preferences:\n";
    std::cout << "Budget: $" << budget << "\n";
    std::cout << "Fuel Type: " << fuelType << "\n";
    std::cout << "Seating Capacity: " << seatingCapacity << "\n\n";

    // Step 4: Apply conditional logic using switch for fuel type and if-else for other conditions
    std::string recommendedCar = "No specific recommendation found for your criteria.";

    if (budget <= 0 || seatingCapacity <= 0) {
        recommendedCar = "Please provide valid positive numbers for budget and seating capacity.";
    } else {
        switch (fuelType[0]) { // Use the first character for switch for simplicity
            case 'p': // petrol
                if (budget < 20000 && seatingCapacity >= 4) {
                    recommendedCar = "A compact petrol hatchback (e.g., 'City Sprint').";
                } else if (budget >= 20000 && budget <= 40000 && seatingCapacity >= 5) {
                    recommendedCar = "A versatile petrol family sedan or SUV (e.g., 'Family Explorer').";
                } else if (budget > 40000 && seatingCapacity >= 5) {
                    recommendedCar = "A powerful petrol luxury car or performance SUV (e.g., 'Veloce Grand').";
                }
                break;
            case 'd': // diesel
                if (budget >= 20000 && budget <= 50000 && seatingCapacity >= 5) {
                    recommendedCar = "A fuel-efficient diesel SUV or sedan for long drives (e.g., 'EcoRoute').";
                } else if (budget > 50000 && seatingCapacity >= 6) {
                    recommendedCar = "A high-torque diesel luxury SUV or minivan (e.g., 'MegaTourer').";
                }
                break;
            case 'e': // electric
                if (budget < 30000 && seatingCapacity >= 2) {
                    recommendedCar = "A compact electric city car with good range (e.g., 'Spark EV').";
                } else if (budget >= 30000 && budget <= 60000 && seatingCapacity >= 4) {
                    recommendedCar = "A mid-range electric sedan or crossover (e.g., 'PowerGlide 400').";
                } else if (budget > 60000 && seatingCapacity >= 5) {
                    recommendedCar = "A premium long-range electric SUV or sedan (e.g., 'Electra Grandeur').";
                }
                break;
            default:
                recommendedCar = "Unsupported fuel type. Please choose petrol, diesel, or electric.";
                break;
        }
    }

    std::cout << "Recommended Car: " << recommendedCar << "\n";

    return 0;
}