What is the difference between {0} and ""?

Question

I would like to know if there is a difference between:

char s[32] = "";

and:

char s[32] = {0};

Thanks.

Answer 1

No there is no difference between both declarations:

char bla[32] = {0};

and

char bla[32] = "";

See the relevant paragraph of the C Standard (emphasis mine):

(C99, 6.7.8p21) "If there are fewer initializers in a brace-enclosed list than there are elements or members of an aggregate, or fewer characters in a string literal used to initialize an array of known size than there are elements in the array, the remainder of the aggregate shall be initialized implicitly the same as objects that have static storage duration."

Answer 2

In that case, there's no difference, both initialise all slots of the array to 0. In general, "" works only for char arrays (with or without modifications like const or unsigned), but {0} works for arrays of all numeric types.

In section 6.7.9 of the standard (n1570), point 21 reads

If there are fewer initializers in a brace-enclosed list than there are elements or members of an aggregate, or fewer characters in a string literal used to initialize an array of known size than there are elements in the array, the remainder of the aggregate shall be initialized implicitly the same as objects that have static storage duration.

so even "" initialises the complete array.

Answer 3

The result of both expressions is the same: an empty string. However, the first is more explicit, thus more readable.