Do every variable declared as pointer have to allocate memory?

Question

Well, I am new to C. I would like to know as my title says.

Suppose I declare pointers as following,

char *chptr1;
char **chptr2;
int *i;
int **ii;
struct somestruct *structvar1;
struct somestruct **structvar2;

Then,

1. Do I need to allocate memory for every variable, before storing data into them?
2. Is there any special case when I do not need to allocate memory for them? for this I know one for char pointer, strdup() which allocate memory itself, we have not to care much about it.
3. Any further suggestions are welcome.

Answer 1

Pointers point at things. It's up to you what you make them point at.

• You can leave them uninitialized and don't use them: int * q; That's a little silly.

• You can make them point to something that exists: int x; int * q = &x;

• You can store the address of dynamically allocated memory in them: int * q = malloc(29);