Context

In embedded C work on NXP Semiconductors platforms such as the MCUXpresso SDK, pointer qualifiers affect API safety, register access, and compiler-enforced correctness. Interviewers use this topic to check whether you can read declarations precisely and reason about mutability.

Core Question

Explain the difference between a pointer to a constant and a constant pointer in C.

Address these points:

1. What does each declaration mean syntactically?
2. In each case, can you modify the pointed-to value, can you change the pointer itself, or both?
3. How would you interpret and use const int *p, int *const p, and const int *const p?

Scope Guidance

Give a clear C-focused explanation, not a generic language-level answer. The interviewer expects you to discuss declaration reading order, valid and invalid operations, and practical usage in firmware or driver code. Small code examples are enough; no long implementation is needed.