运行 ID: 1983

Main.cc:2:7: error: expected nested-name-specifier before ‘namepapers’
 using namepapers std;
       ^~~~~~~~~~
Main.cc: In function ‘int main()’:
Main.cc:5:2: error: ‘cin’ was not declared in this scope
  cin>>a;
  ^~~
Main.cc:5:2: note: suggested alternative:
In file included from Main.cc:1:0:
/usr/include/c++/7/iostream:60:18: note:   ‘std::cin’
   extern istream cin;  /// Linked to standard input
                  ^~~
Main.cc:6:7: warning: statement has no effect [-Wunused-value]
  for(b<=a;b++){
      ~^~~
Main.cc:6:14: error: expected ‘;’ before ‘)’ token
  for(b<=a;b++){
              ^
Main.cc:9:2: error: ‘cout’ was not declared in this scope
  cout<