Note Thanks for Geeks4Geeks, I referred to their posts char * vs string vs char[] and storage for strings in C and here is my very messy note.

char[] and string literal

In short, char[] and string literal are the same. They are interchangable. std::string class is an encapsulation(or interface or wrapper) of char arrays and saves us the effort to manage the array size and provide other convinient functions. Noticeably this is related to C++’s SBRM(Scope based resource manageemnt) aka RAII(resource acquisition is initialization) paradigm. For more detail refer to blogs above.g

char[] vs char*

However, char* is another thing, it is a pointer to the char[], the pointer can be changed to pointer another char[] but it cannot change the element in the array(though it can if the char[] is dynamically allocated and stored on stack using malloc), this is because When a string value is directly assigned to a pointer, in most of the compilers, it’s stored in a read-only block (generally in data segment) that is shared among functions. And we should enforce the pointed string to const to suppress the warning.

Credit: https://www.geeksforgeeks.org/whats-difference-between-char-s-and-char-s-in-c/

Example:

char hello[] = "hello";
char hello1[] = {'h', 'e', 'l', 'l', 'o', '\0'};//now hello and hello1 are the same, both with size of 6(don't forget determinator '\0')
hello1[0] = 'H'; //right, we can change one char element like other type of arrays.

char* hello2 = "hello" // or ={'h', 'e', 'l', 'l', 'o', '\0'} 
*(hello2 +1) = 'H' //wrong, "hello" is in read-only data-segment, we cannot change
//also we are recommended to write as:
const char* hello2 = "hello";

//but if create dynamically allocate the string, we can change the element;
char* hello3 =  (char*)malloc(sizeof(char) * 6)
*(hello3) = 'h';
*(hello3 + 1) = 'e';
*(hello3 + 2) = 'l';
*(hello3 + 3) = 'l';
*(hello3 + 4) = 'o';
*(hello3 + 5) = '\0';

*(hello3) = 'H'; //right, because the content hello3 points to lies on stack like other variables

std::string vs char[]

char[] can convert to std::string implicitly, std::string can convert to char[] with .c_str() or .data()

char hello[] = "hello";
string str_hello = hello; //correct, char[] can implicitly converted to string
auto hello1 = str_hello.c_string(); //correct
char* hello2 = str_hello.data(); //correct