fibonacci dart ffi

dart_ffi.dart

import 'dart:ffi';

// long fibonacci(int n)
typedef NativeFibonacci = Int64 Function(Int64 n);

typedef DartFibonacci = int Function(int n);

class Fibonacci {
  static final dll = DynamicLibrary.open('fibonacci.dll');
  
  final cFibo = dll.lookupFunction<NativeFibonacci, DartFibonacci>('fibonacci');
}

int fibo(int n) {
  if (n <= 1) return 1;
  return fibo(n - 1) + fibo(n - 2);
}

void main(List<String> arguments) {
  var fiboDll = Fibonacci();

  var watch = Stopwatch()..start();

  int n = 45;
  print('n = $n');

  print('Native C: ${fiboDll.cFibo(n)} in ${watch.elapsed}');

  watch..reset()..start();

  print('DartVM: ${fibo(n)} in ${watch.elapsed}');
}

Results on my comupter:
n = 45
Native C: 1836311903 in 0:00:07.551995
DartVM: 1836311903 in 0:00:05.751678