void setup() {
 pinMode(2,INPUT);
 pinMode(A0,INPUT);
 Serial.begin(9600);
 pinMode(5,OUTPUT);

}

void loop() {
Serial.println(digitalRead(2));
Serial.println(analogRead(A0));
delay(100);

int luz=map(A0,0 ,1023, 255,0);
analogWrite(A0,luz);

/*
if(digitalRead(2)==1){
  digitalWrite(5,HIGH);
}
else{digitalWrite(5,LOW);}
*/

}