运行 ID: 9708

Main.cc: In function ‘int main()’:
Main.cc:12:19: error: ‘setprecition’ was not declared in this scope
  cout << fixed << setprecition(4) << aver;
                   ^~~~~~~~~~~~
Main.cc:12:19: note: suggested alternative: ‘sigaction’
  cout << fixed << setprecition(4) << aver;
                   ^~~~~~~~~~~~
                   sigaction