prog.cpp:4:1: error: pasting "@" and "2" does not give a valid preprocessing token
prog.cpp:4: error: stray ‘@’ in program
prog.cpp:4:1: error: pasting "@" and "2" does not give a valid preprocessing token
prog.cpp:4: error: stray ‘@’ in program
prog.cpp:4: error: expected constructor, destructor, or type conversion before ‘(’ token