プログラミング

$ flutter doctorDoctor summary (to see all details, run flutter doctor -v):[✓] Flutter (Channel stable, v1.12.13+hotfix.9, on Mac OS X 10.15.4 19E266, locale ja-JP) [✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)[✓] Xcode - develop for iOS and macOS (Xcode 11.4)[✓] Android Studio (version 3.6)[✓] Connected device (1 available)• No issues found!

$ vi ~/.bash_profile

void misbehave(){  try{    dynamic foo = true;    print(foo++); //runtime error  }catch(e){    print('misbehave() partially handled ${e.runtimeType}.');    rethrow;//呼び出しもとで例外を見れるようにする  }}void main(){  print('start');  try{    misbehave();  }catch(e){    print('main() finished handling ${e.runtimeType}.');  }}

void main(){  //..年齢計算用の良いコード例  int age1 = 50;  checkAge(age1);  //..年齢計算用の良いコード例    //..年齢計算用の悪い(112歳以上)コード例  int age2 = 150;  checkAge(age2);  //..年齢計算用の悪い(112歳以上)コード例}void checkAge(int age){  assert(age < 112, "bad age ${age}");}

class Logger{  void log(dynamic v){    print(DateTime.now().toString() + ' ' + v);  }}main(){    //method cascades　未使用  new Logger().log('program started');  new Logger().log('doing something');  new Logger().log('program finished');    //method cascades使用  new Logger()    ..log('program started')    ..log('doing something')    ..log('program finished');}

main(){  var sunrise = '\u{1f305}';  print(sunrise);}

Error compiling to JavaScript:main.dart:13:1:Error: The return type can't be 'var'.var multiplyMethod2(int a, int b){^^^Error: Compilation failed.