int sw= 4;
int LED = 15;
int value = 0;
int statoled = 0;
void setup() {
 Serial.begin(9600);
 pinMode(sw,INPUT_PULLUP);
 pinMode(LED,OUTPUT);
}

void loop() {
 value = digitalRead(sw);
 Serial.println(value); 
 
if(value==0){
  statoled = not(statoled);
  digitalWrite(LED,statoled);
  } 
  else {digitalWrite(LED,statoled);}
}