In file included from  fluidLevel.cpp:1:
 fluidLevel.h:4:1: error: C++ requires a type specifier for all declarations
pinMode(2, INPUT);                      // set fluid level switch input pin and mode
^~~~~~~
 fluidLevel.h:4:12: error: use of undeclared identifier 'INPUT'
pinMode(2, INPUT);                      // set fluid level switch input pin and mode
           ^
 fluidLevel.cpp:4:9: error: use of undeclared identifier 'digitalRead'
        return digitalRead(2);  // get fluid level switch value and return
               ^
3 errors generated.