char init_port(void);
char operation(void);
char init_port2(void);
char display(void);
int result,num1,num2,row,col,equals;
volatile long i,j;
char array[]={'1','2','3','+','4','5','6','-','7','8','9','/','c','0','=','*'};
volatile char *dirc,*dirf,*dirk,x,*dira,*ptr;
volatile char *outc,*outf,*ink,*outa;
char initialize(void);

char operation1;
char initialize()
{
  dirc = 0x27;dirf=0x30;dirk = 0x107;dira=0x21;
  outc=0x28;outf=0x31;ink=0x106;outa=0x22;
  *dirf=0xff;*dirk=0x00;*dira=0xff;
}

char init_port()
{
  
  int flag = 0;
  while(flag != 1)
  {
    for(int i =0;i<4;i++)
    {
      *outf = 1<<i;
      col = *ink;
     
      if(*ink != 0)
      {
        *ptr=1<<i;
        if(*ptr != 0)
        {
          row = *ptr;
          
          
          
        }
        
        
      }
      if(col == 0b00000001 && row == 0b00000001)
      {
        *outa = 0x06;
        num1=1;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000010 && row == 0b00000001)
      {
        *outa = 0x5b;
        num1=2;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000100 && row == 0b00000001)
      {
        *outa = 0x4f;
        num1=3;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000001 && row == 0b00000010)
      {
        *outa = 0x66;
        num1=4;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000010 && row == 0b00000010)
      {
        *outa = 0x6d;
        num1=5;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000100 && row == 0b00000010)
      {
        *outa = 0x7d;
        num1=6;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000001 && row == 0b00000100)
      {
        *outa = 0x07;
        num1=7;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000010 && row == 0b00000100)
      {
        *outa = 0x7f;
        num1=8;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000100 && row == 0b00000100)
      {
        *outa = 0x6f;
        num1=9;
        delay(500);
        *outa=0x00;
      }
      
      
      if(num1 !=0x00)
      {
        flag = 1;
      }
      
      
      
    }
    
  }
}
char init_port2()
{
  
  int flag = 0;
  while(flag != 1)
  {
    for(int i =0;i<4;i++)
    {
      *outf = 1<<i;
      col = *ink;
     
      if(*ink != 0)
      {
        *ptr=1<<i;
        if(*ptr != 0)
        {
          row = *ptr;
          
          
          
        }
        
        
      }
      if(col == 0b00000001 && row == 0b00000001)
      {
        *outa = 0x06;
        num2=1;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000010 && row == 0b00000001)
      {
        *outa = 0x5b;
        num2=2;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000100 && row == 0b00000001)
      {
        *outa = 0x4f;
        num2=3;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000001 && row == 0b00000010)
      {
        *outa = 0x66;
        num2=4;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000010 && row == 0b00000010)
      {
        *outa = 0x6d;
        num2=5;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000100 && row == 0b00000010)
      {
        *outa = 0x7d;
        num2=6;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000001 && row == 0b00000100)
      {
        *outa = 0x07;
        num2=7;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000010 && row == 0b00000100)
      {
        *outa = 0x7f;
        num2=8;
        delay(500);
        *outa=0x00;
      }
      if(col == 0b00000100 && row == 0b00000100)
      {
        *outa = 0x6f;
        num2=9;
        delay(500);
        *outa=0x00;
      }
      if(num2 !=0x00)
      {
        flag = 1;
      }
      
      
      
    }
    
  }
}
char operation()
{
 
  int flag = 0;
  while(flag != 1)
  {
    for(int i =0;i<4;i++)
    {
      *outf = 1<<i;
      col = *ink;
     
      if(*ink != 0)
      {
        *ptr=1<<i;
        if(*ptr != 0)
        {
          row = *ptr;
          
          
          
        }
        
        
      }
      if(col == 0b00001000 && row == 0b00000001)
      {
        
        operation1 = 1;


      }
      if(col = 0b00001000 && row == 0b00000010)
      {
        operation1 = 2;
      }
      if(col = 0b00001000 && row == 0b00000100)
      {
        operation1 = 3;
      }
      if(col = 0b00001000 && row == 0b00001000)
      {
        operation1 = 4;
      }

      if(operation1 !=0)
      {
        flag = 1;
      }
      
      
      
    }
    
  }

  
}
char display()
{
  volatile char *ddra,*outa;
  ddra = 0x21;
  outa=0x22;
  *ddra=0xff;
  if(operation1 ==1)
  {
    result = num1+num2;
  }
  if(operation1 ==2)
  {
    result = num1-num2;
  }
  if(operation1 ==3)
  {
    result = num1*num2;
  }
  if(operation1 ==4)
  {
    result = num1/num2;
  }
  int flag = 0;
  while(flag != 1)
  {
    for(int i =0;i<4;i++)
    {
      *outf = 1<<i;
      col = *ink;
     
      if(*ink != 0)
      {
        *ptr=1<<i;
        if(*ptr != 0)
        {
          row = *ptr;
          
          
          
        }
        
        
      }
      if(col == 0b00000100 && row == 0b00001000)
      {
        
        equals = 1;


      }
      if(equals !=0)
      {
        flag = 1;
      }
      
      
      
    }
  }
  if(equals == 1 && result == 0)
  {
    *outa=0x3f;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 1)
  {
    *outa=0x06;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 2)
  {
    *outa=0x5b;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 3)
  {
    *outa=0x4f;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 4)
  {
    *outa=0x66;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 5)
  {
    *outa=0x6d;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 6)
  {
    *outa=0x7d;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 7)
  {
    *outa=0x07;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 8)
  {
    *outa=0x7f;
    delay(500);
    *outa=0x00;

  }
  if(equals == 1 && result == 9)
  {
    *outa=0x6f;
    delay(500);
    *outa=0x00;

  }
   

   
   
}
void setup() {
  initialize();
  init_port();
  operation();
  init_port2();
  display();
  delay(500);
  
  

}
void loop() {
  // put your main code here, to run repeatedly:


}