stdFACTORIAL function

dynamic stdFACTORIAL(
  1. dynamic value
)

FACTORIAL：n!

Implementation

dynamic stdFACTORIAL(dynamic value) {
  final n = varToInt(value);
  if (n < 0) return 0;
  int r = 1;
  for (var i = 2; i <= n; i++) {
    r *= i;
  }
  return r;
}