test10.cpp

#include <iostream>
#include <array>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>

namespace n215
{

template<auto... item_codes>
struct InventoryBatch
{
    static constexpr size_t size() { return sizeof...(item_codes); }

    // Let's imagine these codes represent specific inventory items.
    // In the 1950s, maybe they were punch card IDs.

    //  Simulating a "second argument" of the template conceptually:
    //  We can associate a batch ID with each instantiation.
    int batch_id;

    // Simulating a "third argument" conceptually:
    // Perhaps a date code associated with the batch.
    std::string shipment_date;

    // Simulating a "fourth argument" conceptually:
    //  Maybe the warehouse location.
    std::string warehouse_location;

    InventoryBatch(int id, std::string date, std::string location) : batch_id(id), shipment_date(std::move(date)), warehouse_location(std::move(location)) {}

    // A simple function to access the item codes.
    static constexpr auto getItemCodes()
    {
        return std::make_tuple(item_codes...);
    }

    // TO-DO: The core logic - calculating the total value of the batch.
    // This requires looking up prices for each item code.
    double calculateTotalValue() const
    {
        double total = 0.0;
        //  Here's where the magic should happen. Imagine looking up prices
        //  from a ledger based on the item codes. This is the hard part.
        //  Think about how you would iterate through the 'item_codes'
        //  and fetch the corresponding prices.

        //  Consider potential discounts for bulk orders or older stock.
        //  Maybe certain item codes have fixed prices.

        //  Remember, we're in the 1950s, so no fancy databases!
        //  Perhaps a series of if-else statements or a lookup table.

        //  This part is intentionally left for you to implement the core logic.
        //  Think about how to access the individual elements of the
        //  'item_codes' parameter pack.

        //  You might need helper functions or data structures to store prices.

        //  Example:
        //  if constexpr (size() > 0) {
        //      if constexpr (std::get<0>(getItemCodes()) == 123) {
        //          total += getItemPrice(123); // Assume getItemPrice exists
        //      }
        //      // ... and so on for other item codes
        //  }

        //  Good luck! This is where your template metaprogramming skills
        //  will be tested. No simple loops here!

        // TODO: Implement the logic to calculate the total value based on item_codes.













        return sumOfItems();
    }




    constexpr double sumOfItems() const 
    {
        return std::apply([](auto... args) { return (getItemPrice(args) + ...); }, getItemCodes());
    }







  


    // Helper function (you might need to implement this or similar)
    double getItemPrice(auto itemCode) const
    {
        // In a real 1950s system, this might involve looking up in a table.
        // For this exercise, let's just provide some dummy prices.
        if constexpr (std::is_same_v<decltype(itemCode), int>) {
            if (itemCode == 1001) return 5.0;
            if (itemCode == 1002) return 10.0;
            if (itemCode == 1003) return 7.5;
        } else if constexpr (std::is_same_v<decltype(itemCode), char>) {
            if (itemCode == 'A') return 3.0;
            if (itemCode == 'B') return 6.0;
        }
        return 0.0; // Default price
    }
};

} // namespace n215

void run_tests() {
    using namespace n215;

    // Test case 1: Empty batch
    InventoryBatch<> batch1(1, "1955-03-15", "Warehouse A");
    static_assert(batch1.size() == 0, "Test Case 1 Failed: Size should be 0");
    // The total value of an empty batch should be 0.
    // static_assert(batch1.calculateTotalValue() == 0.0, "Test Case 1 Failed: Total value should be 0"); // Will fail until you implement calculateTotalValue

    // Test case 2: Batch with integer item codes
    InventoryBatch<1001, 1002, 1001> batch2(2, "1955-04-01", "Warehouse B");
    static_assert(batch2.size() == 3, "Test Case 2 Failed: Size should be 3");
    // Expected total value: getItemPrice(1001) + getItemPrice(1002) + getItemPrice(1001) = 5.0 + 10.0 + 5.0 = 20.0
    // static_assert(batch2.calculateTotalValue() == 20.0, "Test Case 2 Failed: Incorrect total value"); // Will fail until you implement calculateTotalValue

    // Test case 3: Batch with character item codes
    InventoryBatch<'A', 'B', 'A'> batch3(3, "1955-04-15", "Warehouse A");
    static_assert(batch3.size() == 3, "Test Case 3 Failed: Size should be 3");
    // Expected total value: getItemPrice('A') + getItemPrice('B') + getItemPrice('A') = 3.0 + 6.0 + 3.0 = 12.0
    // static_assert(batch3.calculateTotalValue() == 12.0, "Test Case 3 Failed: Incorrect total value"); // Will fail until you implement calculateTotalValue

    // Test case 4: Batch with mixed item codes
    InventoryBatch<1001, 'B', 1003> batch4(4, "1955-05-01", "Warehouse C");
    static_assert(batch4.size() == 3, "Test Case 4 Failed: Size should be 3");
    // Expected total value: getItemPrice(1001) + getItemPrice('B') + getItemPrice(1003) = 5.0 + 6.0 + 7.5 = 18.5
    // static_assert(batch4.calculateTotalValue() == 18.5, "Test Case 4 Failed: Incorrect total value"); // Will fail until you implement calculateTotalValue

    // Test case 5: Batch with duplicate item codes
    InventoryBatch<1002, 1002, 1002> batch5(5, "1955-05-15", "Warehouse B");
    static_assert(batch5.size() == 3, "Test Case 5 Failed: Size should be 3");
    // Expected total value: getItemPrice(1002) + getItemPrice(1002) + getItemPrice(1002) = 10.0 + 10.0 + 10.0 = 30.0
    // static_assert(batch5.calculateTotalValue() == 30.0, "Test Case 5 Failed: Incorrect total value"); // Will fail until you implement calculateTotalValue

    std::cout << "All static asserts passed (initial checks). Implement calculateTotalValue to run the value checks." << std::endl;
}

int main() {
    run_tests();
    return 0;
}