What is the difference between char a[] = ?string?; and char *p = ?string?;?

Question

As the heading says, What is the difference between

char a[] = ?string?; and 
char *p = ?string?;  

This question was asked to me in inter

Answer 1

a declares an array of char values -- an array of chars which is terminated.

p declares a pointer, which refers to an immutable, terminated, C string, whose exact storage location is implementation-defined. Note that this should be const-qualified (e.g. const char *p = "string";).

If you print it out using std::cout << "a: " << sizeof(a) << "\np: " << sizeof(p) << std::endl;, you will see differences their sizes (note: values may vary by system):

a: 7
p: 8

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Here what is ? operator? Is it a part of a string or it has some specific meaning?

char a[] = ?string?

I assume they were once double quotes "string", which potentially were converted to "smart quotes", then could not be represented as such along the way, and were converted to ?.