运行 ID: 137027

Main.cc: In function ‘int main()’:
Main.cc:11:5: error: ‘cin’ was not declared in this scope
     cin>>a>>b>>c>>d; 
     ^~~
Main.cc:11:5: note: suggested alternative: ‘main’
     cin>>a>>b>>c>>d; 
     ^~~
     main
Main.cc:20:13: error: ‘cout’ was not declared in this scope
             cout<