#include <Servo.h>

Servo myservo;
int buttonPin = 4;            
int buttonState;              
int lastButtonState = HIGH;   
int currentAngle = 90;        
int step = 30;               
bool direction = true;        

void setup() {
  myservo.attach(9);               
  pinMode(buttonPin, INPUT_PULLUP); 
  myservo.write(currentAngle);     
}

void loop() {
  buttonState = digitalRead(buttonPin); 

  if (buttonState == LOW && lastButtonState == HIGH) {
    if (direction) {
      currentAngle += step;
      if (currentAngle >= 180) {   
        currentAngle = 180;
        direction = false;        
      }
    } else {
      currentAngle -= step;
      if (currentAngle <= 0) {   
        currentAngle = 0;
        direction = true;         
      }
    }

    myservo.write(currentAngle);  
    delay(200);                   
  }

  lastButtonState = buttonState; 
}