42 lines
1.2 KiB
Dart
42 lines
1.2 KiB
Dart
|
// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
|
||
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
||
|
|
// BSD-style license that can be found in the LICENSE file.
|
||
|
|
|
||
|
|
import 'package:logging/logging.dart';
|
||
|
|
|
||
|
|
final log = Logger('ExampleLogger');
|
||
|
|
|
||
|
|
/// Example of configuring a logger to print to stdout.
|
||
|
|
///
|
||
|
|
/// This example will print:
|
||
|
|
///
|
||
|
|
/// INFO: 2021-09-13 15:35:10.703401: recursion: n = 4
|
||
|
|
/// INFO: 2021-09-13 15:35:10.707974: recursion: n = 3
|
||
|
|
/// Fibonacci(4) is: 3
|
||
|
|
/// Fibonacci(5) is: 5
|
||
|
|
/// SHOUT: 2021-09-13 15:35:10.708087: Unexpected negative n: -42
|
||
|
|
/// Fibonacci(-42) is: 1
|
||
|
|
void main() {
|
||
|
|
Logger.root.level = Level.ALL; // defaults to Level.INFO
|
||
|
|
Logger.root.onRecord.listen((record) {
|
||
|
|
print('${record.level.name}: ${record.time}: ${record.message}');
|
||
|
|
});
|
||
|
|
|
||
|
|
print('Fibonacci(4) is: ${fibonacci(4)}');
|
||
|
|
|
||
|
|
Logger.root.level = Level.SEVERE; // skip logs less then severe.
|
||
|
|
print('Fibonacci(5) is: ${fibonacci(5)}');
|
||
|
|
|
||
|
|
print('Fibonacci(-42) is: ${fibonacci(-42)}');
|
||
|
|
}
|
||
|
|
|
||
|
|
int fibonacci(int n) {
|
||
|
|
if (n <= 2) {
|
||
|
|
if (n < 0) log.shout('Unexpected negative n: $n');
|
||
|
|
return 1;
|
||
|
|
} else {
|
||
|
|
log.info('recursion: n = $n');
|
||
|
|
return fibonacci(n - 2) + fibonacci(n - 1);
|
||
|
|
}
|
||
|
|
}
|