How can I understand this static local variable?

[northfly]

the execution of the following code will generate numbers from 1 through 10, instead of a serial of 1, why?

size_t count_calls() {
    static size_t ctr=0;
    return ++ctr;
}

int main() {
    for(size_t i=0; i!= 10; ++i)
        cout<<count_calls()<<endl;
}

Isn't this"static size_t ctr=0" executed every time? and Initialized to 0 every time? Even the memory remains but the value can be re-initialized, right?

[Dufresne]

Search for definition of keyword "static"

[Albatross]

static is a cute keyword.

I'm not 100% sure of what I does because I only rarely use it, but when I do use it, it's when I don't want my variable to be reinitialized, and your variable indeed isn't reinitialized here. You can still use ctr = 0 in a separate statement and get your ten 1s, but like that, it will just keep on counting.

If you axe the static, then your function will print all ones.

-Albatross

[northfly]

Thanks guys, may be there are some internal mechanism to prevent a static object to be reinitialized, at least I have a clue now, thanks.