On Thursday 08 of September 2011 11:41:05 Winston Kodogo wrote:
> (...)
> I'm puzzled as to why the line "int nigel = 1;" is syntactically OK,
> and although it seems to have declared the variable "nigel" - else the
> following code would fail to compile - has failed to give it the
> initial value of 1, as requested.
consider the `switch' statement a switchboard that jumps to one of the
`case's.
nigel is not getting initialized because this code path is not executed -- as
it is not part of any `case' taken by the switch.
an `automatic' (non-static) variable is initialized by a piece of code, the
code gets executed whenever flow of control reaches that particular place.
a static variable (`static int inigel = 1') is initialized by static data,
before any code gets executed -- and only once. static will do what you
expect.
this is why you can place a static variable outside of any function and it
still gets initialized.
both kinds have their uses, in different situations.
for reference:
for (int i = 0; i < 8; ++i) {
int nigel = 1; // this emits some code that gets executed for every loop and
resets the var to `1'
printf("nigel: %d,", nigel);
++nigel;
}
will print: nigel: 1,nigel: 1,nigel: 1, ...
on the other hand:
for (int i = 0; i < 8; ++i) {
static int nigel = 1; // this var is initialized just once before main()
begins and doesn't reset
printf("nigel: %d,", nigel);
++nigel;
}
will print: nigel: 1,nigel: 2,nigel: 3, ...
--
dexen deVries
[[[↓][→]]]
For example, if the first thing in the file is:
an XML parser will recognize that the document is stored in the traditional
ROT13 encoding.
(( Joe English, http://www.flightlab.com/~joe/sgml/faq-not.txt ))
