extFIB function

dynamic extFIB(
  1. dynamic value
)

FIB(n): the nth Fibonacci number (0-based)

Implementation

dynamic extFIB(dynamic value) {
  final n = varToInt(value);
  if (n < 0) return 0;
  if (n == 0) return 0;
  int a = 0, b = 1;
  for (var i = 2; i <= n; i++) {
    final c = a + b;
    a = b;
    b = c;
  }
  return b;
}