// C++ code
//
#include <Servo.h>

int p = 0;

Servo servo_2;

void setup()
{
  servo_2.attach(2, 500, 2500);
  pinMode(3, INPUT);
  pinMode(4, INPUT);

  p = 0;
  servo_2.write(p);
}

void loop()
{
  if (digitalRead(3) == HIGH && p < 180) {
    p += 20;
    servo_2.write(p);
  }
  if (p == 180) {
    p = 0;
    servo_2.write(p);
  }
  if (digitalRead(4) == HIGH && p > 0) {
    p += -20;
    servo_2.write(p);
  }
  if (p == 0) {
    p = 0;
    servo_2.write(p);
  }
  delay(100); // Wait for 100 millisecond(s)
}