#include <Servo.h>

const int BUTTON_PIN = 7;
const int SERVO_PIN  = 2;

Servo servo;

int angle = 0;
int lastButtonState;
bool ButtonState;

void setup() {
  Serial.begin(9600);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  servo.attach(SERVO_PIN);

  servo.write(angle);
  ButtonState = digitalRead(BUTTON_PIN);
}

void loop() {
  lastButtonState = ButtonState;
  ButtonState = digitalRead(BUTTON_PIN);

  if(lastButtonState = !lastButtonState) {
    while(digitalRead(BUTTON_PIN) == HIGH);
    delay(100);
    
    Serial.println("The button is pressed!");

    if(angle == 0){
      angle = 180;
    } else if(angle == 180){
      angle = 0;
    }
    servo.write(angle);
  }
}