sketch_may16c:5:1: error: 'HX711' does not name a type

 HX711 scale(DOUT, CLK); //엠프 핀 선언

 ^~~~~

C:UsersFetusDocumentsArduinosketch_may16csketch_may16c.ino: In function 'void setup()':

sketch_may16c:9:3: error: 'scale' was not declared in this scope

 scale.set_scale(calibration_factor); //스케일 지정

 ^~~~~

C:UsersFetusDocumentsArduinosketch_may16csketch_may16c.ino:9:3: note: suggested alternative: 'scanf'

 scale.set_scale(calibration_factor); //스케일 지정

 ^~~~~

 scanf

C:UsersFetusDocumentsArduinosketch_may16csketch_may16c.ino: In function 'void loop()':

sketch_may16c:15:16: error: 'scale' was not declared in this scope

 Serial.print(scale.get_units(), 1); //무제 출력

 ^~~~~

C:UsersFetusDocumentsArduinosketch_may16csketch_may16c.ino:15:16: note: suggested alternative: 'scanf'

 Serial.print(scale.get_units(), 1); //무제 출력

 ^~~~~

 scanf

exit status 1

'HX711' does not name a type