scanf problem

[ABS]

As poppy_123 mentioned the C++ syntax is nicer when using cin, unfortunately if you can only use C, then you won't be able to use it.

I also would mention that IMO using the age array like this makes more sense (replace cin, with your preference of reading user input as needed and cout with your printf command if using strictly C):

int age_count=0;
int age_needed=3;
int age[age_needed];
int age;
while (age_count < age_needed) {
  cout << "Enter name for user #" << age_count+1 << ": ";
  cin>>age;
  if (age < 18) {
    cout << "Age must be 18+\n";
  }
  else {
    age[age_count]=age;
    age_count++;
  }
}

[NOTE] I didn't test the above code, so don't complain if it I made a syntax error