Array of char* should end at '\0' or "\0"?

Question

Lets say we have an array of char pointers

char* array[] = { "abc", "def" };

Now what should be put in the end ?

char* array[] = { "abc", "def", '\0' };

or

char* array[] = { "abc", "def", "\0" };

Though, both works. We only have to put the condition to check the end accordingly

like

array[ index ] != '\0';

or

array[ index ] != "\0";

My question is which one is the better way? Which is used by most programmers?

Edit

Most answers say that NULL is better than '\0' and "\0". But I always thought that

NULL is same as '\0' which is same as 0x0 or 0

Is it wrong?

Answer 1

I would end it with NULL. Why? Because you can't do either of these:

array[index] == '\0'
array[index] == "\0"

The first one is comparing a char * to a char, which is not what you want. You would have to do this:

array[index][0] == '\0'

The second one doesn't even work. You're comparing a char * to a char *, yes, but this comparison is meaningless. It passes if the two pointers point to the same piece of memory. You can't use == to compare two strings, you have to use the strcmp() function, because C has no built-in support for strings outside of a few (and I mean few) syntactic niceties. Whereas the following:

array[index] == NULL

Works just fine and conveys your point.