something interesting on static~

Hi, folks~

Let's see the function below first:

PHP Code:

---

void sta()
{
  static int a;
  a=0;
  a++;
  cout << "static a= " << a << endl;
} 


---

No doubt we cuold get the value 0 all the time.
and then the next function:

PHP Code:

---

void sta()
{
  static int a=0;
  a++;
  cout << "static a= " << a << endl;
} 


---

Please Check the difference, a bit interesting~:)

>a=0;

this is assignment.

>static int a=0;

this is initialization.

the difference is that static variables are only initialized once, where-as they can be assigned to unlimited times.

No-one is right. (Just went over this one today as a matter of fact.)

I believe Mr. Stroustrup refers to a static variable as one "with memory", i.e. it isn't destroyed at the end of scope.

From what I could discern, it can be "played wiith" within its scope (not outside), but will retain its most recent value.

Thanks, Black. Good stuff. (And, thanks, no-one, for explaining it.)

-Skipper

yep. From the input we could include static acts just like somewhat global inside functions. It initialize only once, and it ignores the defination when was calling again, just the following code executes. :)

thanx no-one and skipper, your explaination make it clear now~ ;)

>a bit interesting
Another interesting fact about static variables with local scope is that they are automatically initialized to zero, just like global variables. :)

-Prelude

Quote:

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Originally posted by Prelude
>a bit interesting
Another interesting fact about static variables with local scope is that they are automatically initialized to zero, just like global variables. :)

-Prelude

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oh, yes it is ! fantastic~ :p

thanx Prelude for mention this.

Quote:

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Another interesting fact about static variables with local scope is that they are automatically initialized to zero, just like global variables.

---

And - are we getting some mileage out of this, or what? - once an initializing statement, if any, is encountered, it is ignored afterward.

That is, a statement such as

Code:

---

static int x = 0;

---

found within a loop structure does not reset the current value of 'x' to '0'. (The little devil takes on a life of its own, it seems. :))

Thanks, Prelude.

-Skipper