Difference between char* and char[]

Question

I know this is a very basic question. I am confused as to why and how are the following different.

char str[] = \"Test\";
char *str = \"Test\";

Answer 1

Starting from C++11, the second expression is now invalid and must be written:

const char *str = "Test";

The relevant section of the standard is Appendix C section 1.1:

Change: String literals made const

The type of a string literal is changed from “array of char” to “array of const char.” The type of a char16_t string literal is changed from “array of some-integer-type” to “array of const char16_t.” The type of a char32_t string literal is changed from “array of some-integer-type” to “array of const char32_t.” The type of a wide string literal is changed from “array of wchar_t” to “array of const wchar_t.”

Rationale: This avoids calling an inappropriate overloaded function, which might expect to be able to modify its argument.

Effect on original feature: Change to semantics of well-defined feature.