Example: Car Recommendation using Nested If-Else in C++

// Car Recommendation using Nested If-Else
#include <iostream>
#include <string>
#include <limits> // Required for numeric_limits

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

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

    // Step 2: Get budget input from the user
    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(); // Clear error flag
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // Discard invalid input
    }
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // Consume the rest of the line

    // Step 3: Get fuel type input from the user
    std::cout << "Enter desired fuel type (petrol, diesel, electric): ";
    std::getline(std::cin, fuelType);

    // Step 4: Get seating capacity input from the user
    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(); // Clear error flag
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // Discard invalid input
    }
    std::cout << "\n"; // Add a newline for better readability

    // Step 5: 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 6: Apply conditional logic to recommend a car
    std::string recommendedCar = "No specific recommendation found for your criteria.";

    if (budget < 20000) {
        if (fuelType == "petrol" && seatingCapacity >= 4) {
            recommendedCar = "A compact hatchback or entry-level sedan (e.g., 'City Commuter').";
        } else if (fuelType == "electric" && seatingCapacity >= 2) {
            recommendedCar = "A small electric city car (e.g., 'Eco Pod').";
        }
    } else if (budget >= 20000 && budget <= 40000) {
        if (fuelType == "petrol" && seatingCapacity >= 5) {
            recommendedCar = "A mid-range family sedan or compact SUV (e.g., 'Comfort Cruiser').";
        } else if (fuelType == "diesel" && seatingCapacity >= 5) {
            recommendedCar = "A fuel-efficient diesel SUV for longer trips (e.g., 'Mileage Master').";
        } else if (fuelType == "electric" && seatingCapacity >= 4) {
            recommendedCar = "A modern electric sedan or crossover (e.g., 'VoltStream 300').";
        }
    } else { // budget > 40000
        if (fuelType == "petrol" && seatingCapacity >= 5) {
            recommendedCar = "A premium sedan or a large SUV (e.g., 'Luxury Drive XL').";
        } else if (fuelType == "electric" && seatingCapacity >= 5) {
            recommendedCar = "A high-performance luxury electric vehicle (e.g., 'ElectroStar Grand').";
        }
    }

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

    return 0;
}