#include <Servo.h>

Servo myservo;

int pos = 0;
int step = 1;

const int button_a_Pin = 2;
const int button_b_Pin = 12;
const int button_c_Pin = 8;
const int button_d_Pin = 7;

void setup() {
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(2, INPUT);
  pinMode(12, INPUT);
  pinMode(8, INPUT);
  pinMode(7, INPUT);
  myservo.attach(11);
} 

void loop() {
  int onOff = digitalRead(button_b_Pin);
  
  // Problem 1
  if (digitalRead(button_a_Pin) == HIGH) {
    digitalWrite(5, LOW);
    digitalWrite(6, LOW);
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
  } else {
    digitalWrite(5, HIGH);
    digitalWrite(6, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }

  // Problem 2 & 3
  while (onOff) {
    digitalWrite(5, LOW);
    digitalWrite(6, LOW);
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    if (digitalRead(button_c_Pin) == HIGH) {
      onOff = 0;
    }
  }

  // Problem 4
  while (digitalRead(7)) {
    {
    //send servo to 45° and hold in that position for 250 ms
    myservo.write(45);
    delay(250);

    //send servo to 135° and hold in that position for 350 ms
    myservo.write(135);
    delay(350);
    }
  }
}