Button on and off plus light sensor for arduino

#define LED 13 #define BUTTON 7 int val = 0; int old_val = 0; int state = 0; const int analogInPin = A0; const int analogOutPin = 4; int sensorValue = 0; int outputValue = 0; void setup() { pinMode(LED, OUTPUT); pinMode(BUTTON, INPUT); Serial.begin(9600); } void loop(){ val = digitalRead(BUTTON); // check if there was a transition if ((val == HIGH) && (old_val == LOW)){ state = 1 - state; } old_val = val; if (state == 1) { digitalWrite(LED, HIGH); } else { digitalWrite(LED, LOW); } // read the analog in value: sensorValue = analogRead(analogInPin); // map it to the range of the analog out: outputValue = map(sensorValue, 100, 200, 255, 0); // change the analog out value: analogWrite(analogOutPin, outputValue); Serial.print("sensor = " ); Serial.print(sensorValue); Serial.print("\t output = "); Serial.println(outputValue); delay(2); }