112. Multilevel Driver Initialization

In embedded firmware, drivers are commonly layered to separate responsibilities and ensure correct hardware bring-up.
A typical structure looks like:

• A core driver that initializes shared system resources
• A communication driver that sets up protocol-level behavior
• A device-specific driver that applies final configuration

In C++, multilevel inheritance guarantees a strict constructor execution order, which is critical in such designs.

Your task is to implement and verify constructor execution order in a three-level inheritance hierarchy that mimics a real firmware driver stack.

Scenario

You must implement the following class hierarchy:

CoreDriver
   ↓
CommDriver
   ↓
SpiDriver

Each class represents a firmware layer and performs initialization in its constructor.

Requirements

Step 1: CoreDriver

• Define a class CoreDriver

• Provide a constructor that prints exactly:

  Core driver initialized
  

Step 2: CommDriver

• Define a class CommDriver
• Publicly inherit from CoreDriver

• Provide a constructor that prints exactly:

  Comm driver initialized
  

Step 3: SpiDriver

• Define a class SpiDriver
• Publicly inherit from CommDriver
• Constructor requirements:
  • Accepts one integer parameter speed

  • Prints exactly:

    SPI driver initialized
    

  • Stores the speed value internally

• Provide a member function that prints:

  SPI speed <speed>
  

Input

• One integer value:

  speed 

Program Flow (Mandatory Order)

1. Read integer speed from standard input
2. Create a SpiDriver object using speed
3. Constructor execution order must be:
   • CoreDriver
   • CommDriver
   • SpiDriver
4. Call the function that prints the SPI speed

Example Input

8

Example Output

Core driver initialized
Comm driver initialized
SPI driver initialized
SPI speed 8 

Constraints (Strict)

• Use multilevel inheritance only
• Inheritance must be public
• Do NOT use:
  • Virtual functions
  • Dynamic memory allocation (new, malloc)
  • Composition
• Output text and order must match exactly
• Use only standard input and output
• No additional logging or formatting