#include <LiquidCrystal.h>

  struct opCode
{
  unsigned int digits : 3;
};
  struct ALU_Driver
{
  int A;
  int B;
  opCode operation;
};
  ALU_Driver arr[8];
  int Result_Array[8];

  LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
  int pushed = 0;

  int readBtn(){
  pushed = analogRead(0);
  if(pushed == 1023) return 1;
  if(pushed == 1021) return 2;
  return pushed;
}

  int index = 0;
  int btn = 0;
 void Print(int index){
  lcd.setCursor(0, 0);
  String temp = "";
  switch (arr[index].operation.digits) {
  case 000:
    temp="+";
    break;
  case 001:
    temp="-";
    break;
  case 010:
    temp="<<";
    break;
  case 011:
    temp=">>";
    break;
  case 100:
    temp=">>";
    break;
  case 101:
    temp="&";
    break;
  case 110:
    temp="|";
    break;
  case 111:
    temp="^";
    break;
  default:
    break;
}

  lcd.print(arr[index].A + temp + arr[index].B + "=" + Result_Array[index]);
}
void setup() {
  lcd.begin(16, 2);

  arr[0].A=3;
  arr[0].B=5;
  arr[0].operation.digits=000;

  arr[1].A=13;
  arr[1].B=7;
  arr[1].operation.digits=001;

  arr[2].A=22;
  arr[2].B=3;
  arr[2].operation.digits=010;

  arr[3].A=33;
  arr[3].B=1;
  arr[3].operation.digits=011;

  arr[4].A=33;
  arr[4].B=-1;
  arr[4].operation.digits=100;

  arr[5].A=23;
  arr[5].B=32;
  arr[5].operation.digits=101;

  arr[6].A=37;
  arr[6].B=20;
  arr[6].operation.digits=110;

  arr[7].A=17;
  arr[7].B=28;
  arr[7].operation.digits=111;

  int i=0;
  for (i=0;i<8;i++) {
     switch (arr[i].operation.digits) {
  case 000:
    Result_Array[i]=arr[i].A + arr[i].B;
    break;
  case 001:
    Result_Array[i]=arr[i].A - arr[i].B;
    break;
  case 010:
    Result_Array[i]=arr[i].A << arr[i].B;
    break;
  case 011:
    Result_Array[i]=arr[i].A >> arr[i].B;
    break;
  case 100:
    if(arr[i].B<0){
     arr[i].B*=-1;;
     Result_Array[i]=arr[i].A << arr[i].B;
    }else{
     Result_Array[i]=arr[i].A >> arr[i].B;
    }
    break;
  case 101:
    Result_Array[i]=arr[i].A & arr[i].B;
    break;
  case 110:
    Result_Array[i]=arr[i].A | arr[i].B;
    break;
  case 111:
    Result_Array[i]=arr[i].A ^ arr[i].B;
    break;
  default:
    break;
}
}
  Print(index);
}
void loop() {
  btn = readBtn();
  if(btn == 1){
    lcd.clear();
    index--;
    if(index < 0)
      index = 7;
    delay(150);
    Print(index);
  }else if(btn == 2){
    lcd.clear();
    index = (index + 1) % 8;
    delay(150);
    Print(index);
  }

}