C++ concepts

The four storage classes in C are auto (automatic), register, static, and extern (external). Automatic variables have local scope and lifetime. Static variables retain their value between function calls. External variables are visible across multiple files. Global is not a storage class - it describes scope, not storage duration.

A null pointer is a special pointer value that points to no memory location and is typically represented as zero. Void pointers can point to any data type but are not necessarily null. The question describes a null pointer, which can be assigned to any pointer type and conventionally has the value zero.

In C++, the 'new' and 'delete' operators can be overloaded. Statement 'a' is false because members of a 'struct' are public by default (unlike 'class'). Statement 'c' is false because the assignment operator (=), subscript operator ([]), and function call operator (()) must be overloaded as non-static member functions.

Inline functions are expanded at compile time - the function call is replaced by the actual function code, eliminating function call overhead. This is a compiler optimization that trades code size for execution speed. Virtual functions use dynamic dispatch, static functions have file scope, and friend functions access private data - none of these replace the call with code at compile time.

Abstraction involves showing only essential features and hiding implementation details from the user. It focuses on what an object does rather than how it does it. Encapsulation bundles data and methods together. Information hiding is a related principle but more restrictive. Polymorphism allows objects of different types to be treated uniformly.