Why is this function correct?

[Tung]

is_leap_year <- function(year) {
  # If year is div. by 400 return TRUE
  if(is_divisible_by(year, 400)) {
    return(TRUE)
  }
  # If year is div. by 100 return FALSE
  if(is_divisible_by(year, 100)) {
    return(FALSE)
  }  
  # If year is div. by 4 return TRUE
  if(is_divisible_by(year, 4)) {
    return(TRUE)
  }
  # Otherwise return FALSE
  FALSE
}

Notice that here if year is div. by 100, then return FALSE. So my understanding is if I input year==2000, then I just get FALSE. However, it gives me correct TRUE. How come?

[HanOostdijk]

Because in this case the first condition is met, the return statement will be executed and therefore further conditions will not be checked.