I can explain you lot of this behavoir, but not in english... if you want I can do it in spanish...
for example, is stupid said, that C reuse a var between several functions, only is the space for non-static vars...
this give you 42, too.
int b = 42;
the first example, is curious, but is logic... depend on stack state machine based implementation or direct interpreter...
well, who did this document?