Mã chấm: 267783

Main.cc: In function ‘int main()’:
Main.cc:8:5: error: ‘cin’ was not declared in this scope
     cin>>a>>b>>x>>y;
     ^~~
Main.cc:8:5: note: suggested alternative: ‘sin’
     cin>>a>>b>>x>>y;
     ^~~
     sin
Main.cc:9:5: error: ‘cout’ was not declared in this scope
     cout<