char input;

void setup() {
  // put your setup code here, to run once:
  pinMode(12, OUTPUT);
  Serial.begin(9600);
  Serial.println("Arduino Control Of LED Using Serial Monitor");
}

void loop() {
  // put your main code here, to run repeatedly:
  if(Serial.available())
  {
    input = Serial.read();
  }
  if(input=='1')
  {
    digitalWrite(12, HIGH);
  }
  if(input=='0')
  {
    digitalWrite(12, LOW);
  }
}