120. Override Correctness Pitfalls

In embedded firmware, driver interfaces often define virtual functions that derived drivers must override to provide device-specific behavior.

Two common and dangerous mistakes occur in real systems:

• A derived driver accidentally changes the function signature and forgets to use override, causing a silent runtime bug where the base implementation executes.
• A derived driver uses override with an incorrect function signature, causing a compile-time error.

Both situations are critical to understand and avoid in production firmware.

In this problem, you are given two drivers with different override mistakes:

• SPI driver demonstrates a silent override failure (signature mismatch without override)
• I2C driver demonstrates a compile-time detected override mismatch (incorrect signature with override)

Your task is to fix the program so that:

• Both drivers correctly override the base virtual function
• The program compiles successfully
• Runtime polymorphism works correctly for both drivers

This problem enforces professional override discipline required in production embedded C++.

Input / Program Flow:

One integer value is read from standard input.

Driver selection rules:

• If input is 0 → use the SPI driver
• If input is 1 → use the I2C driver

Program flow:

• Read one integer value
• Create the selected driver object
• Store its address in a base-class pointer
• Call the virtual function through the base-class pointer

Output:

If input is 0, the program must print:

SPI driver processing

If input is 1, the program must print:

I2C driver processing

Output requirements:

• Exactly one line of output
• Exact text and spacing must match
• Output must be produced via a polymorphic call

Constraints:

• Language standard: C++11
• Do NOT change function names
• Do NOT change how the base-class pointer is used
• Do NOT add new virtual functions
• Do NOT use dynamic memory allocation
• You MUST use the override keyword correctly
• You MAY correct function signatures in derived classes
• Output must match exactly