rand() works strangely. What is the problem?

Question

C++ / C#

Hey! I have a function:

char generate_asterisk_or_space() {
  srand(static_cast<int>(time(0)));
  int num = rand() % 2;
  switch (num) {
  case 0:
    return '_';
  case 1:
    return '*';
  default:
    return '_';
  }
}

Its essence is to simply return * or _. With it, I form an array, but! It produces exactly the same characters during a normal launch ... Oops!
Another but, is that if I debug the code step by step, everything works as expected - a random set of characters is formed. Tried some tricks with time delay and passing different parameters to srand() - didn't help.
What is the reason for such strange behavior?

Answer 1

Set the seed once - before forming the array. With a release build, the value returned by time is most likely the same. Example:

srand(static_cast<int>(time(0)));
for( int i =0; i<array_length; i++){
     rand_array[i] = generate_asterisk_or_space();
}

Answer 2

With it, I form an array,

Those. you call it in a loop, i.e. call srand(static_cast(time(0))); many times in a short time. Continue?
Question: why are you doing this inside this function?

Answer 3

And how else to work if the same starting value is always set?