How does the "double" return work in this task?

Question

I dont understand how this code works

bool key_check(string key);
int main(int argc, string argv[])
{
if (argc == 2 && key_check(argv[1]))
printf("ok\n");
}

bool key_check(string key)
{
for (int i= 0, n = strlen(key); i < n; i++) {
if (!(key[i] >= '0' && key[i] <= '9')) {
return false;
return true;
}
as i understand it means:
if key[i] is NOT between 0 and 0 - then rerutn false. But what return true means?

for example argv[1] = "2a", strlen =n= 2
when i = 0
'2' is between '0' and '9'. - it will do nothing and go to the next iteration right?

next iteration i = 1
'a' is not betwen '0' and '9', so because of "!" in the beginning of the condition it will retrun false

what "return true" does then?

Answer 1

Return true should be below the for loop.
You are missing two } in your code one for the if statement and one for the for loop.