Main.cc:1:2: error: invalid preprocessing directive #incoude #incoude ^ Main.cc:2:17: error: 'str' is not a namespace-name using namespace str; ^ Main.cc:2:20: error: expected namespace-name before ';' token using namespace str; ^ Main.cc: In function 'int main()': Main.cc:6:5: error: 'cout' was not declared in this scope cout<a+b<<endl; ^ Main.cc:6:16: error: 'endl' was not declared in this scope cout<<a+b<<endl; ^