Error in my Arduino code " error: expected unqualified-id before ‘if’ "
C is procedural language and code is compiled. You cannot put code beyond procedure as you try to do in mentioned if. Remaining code following this point is nonsense. Do you mean you can put second loop() based on if condition ? I recommend to start learning programming C before using Arduino. In C you can do such a idea using preprocessor directives IF, ELSE, ENDIF.