What does star with identifier mean in c language?

Answer 1

It depends on the context. If used in a declaration, it means that the identifier is declared a pointer to a named type. If used in an expression, it means that you wish to dereference a pointer. A pointer is used to store memory addresses. Dereferencing a pointer allows the programmer to access the value stared in the memory address. In other words, it provides indirect access to the value stored in the memory address being pointed at.

int i, *p; /* declare an integer and a pointer to an integer */

p = &i; /* store the address of i in p (point to i)*/

*p = 42; /* store the value 42 in that address (dereference) */

assert (i==42); /* assert that i now holds the value 42 */
It mean the content of that identifier.