/in/foo.cc: In function 'int main()':
/in/foo.cc:5:11: error: unable to find string literal operator 'operator""Hello' with 'const char [1]', 'long unsigned int' arguments
     cout<<""Hello,world!"";
           ^~~~~~~
/in/foo.cc:5:19: error: 'world' was not declared in this scope
     cout<<""Hello,world!"";
                   ^~~~~