Question

when i try

    char bla[32] = "foobar";
    int i;
    putchar(bla[i]);

with strlen(bla) < i < 32, bla[i] is always \0. but isn’t this in fact undefined behaviour, and should be avoided?

Answer 1

C89 spec, section 8.7 “Initialization”:

If the array has fixed size, the
number of initializers may not exceed
the number of members of the array; if
there are fewer, the trailing members
are initialized with 0.

So, in your usage, the trailing characters are initialized with zeros.