volatile char *portf,*outf,*portk,*outk,*porta,*portc,*rowa,*colc,temp =0x3F,out = 0x3F,temp1,temp2;
int a=0,b=0,track=0,choice=0,c=0,num1=0,num2=0,d=0,result=0,start=0,resultSize=0,Echeck=0,buttonPressed=0;
void row2();
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  porta = 0x21;
  portc = 0x27;
  *porta = 0xFF;
  *portc = 0x00;
  rowa = 0x22;
  colc = 0x26;
  portk = 0x107;
  outk = 0x108;
  portf = 0x30;
  outf = 0x31;
  *portf = 0xFF;
  *portk = 0xFF;
  *colc =0;

}

void Delay(){

for(volatile long int j=0;j<90000;j++);
return;
}

 // row1
 void row1(){
*rowa = 0x01;

switch(*colc){
   
  case 0x01:

  if(track==0 && choice==0){
    a = 1;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 1;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 1;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 1;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 1;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 1;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 1;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 1;
    num2 = 1000*a +100*b + 10*c +d;
  }
  track++;
  Delay();

  break;


  case 0x02:
  
  if(track==0 && choice==0){
    a = 2;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 2;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 2;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 2;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 2;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 2;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 2;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 2;
    num2 = 1000*a +100*b + 10*c + d;
  }
track++;
Delay();
  break;

  case 0x04:
  
  if(track==0 && choice==0){
    a = 3;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 3;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 3;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 3;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice !=0){
    a = 3;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 3;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 3;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice !=0){
    d = 3;
    num2 = 1000*a +100*b + 10*c + d;
  }
  
track++;
Delay();
  break;
}

  return;
}


void row2(){
*rowa = 0x02; 

switch(*colc){


  case 0x01:

  if(track==0 && choice==0){
    a = 4;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 4;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 4;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 4;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 4;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 4;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 4;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 4;
    num2 = 1000*a +100*b + 10*c + d;
  }
  track++;
  Delay();
  break;

  case 0x02:
  
  if(track==0 && choice==0){
    a = 5;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 5;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 5;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 5;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 5;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 5;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 5;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 5;
    num2 = 1000*a +100*b + 10*c + d;
  }
  track++;
  Delay();
  break;

  case 0x04:
  
  if(track==0 && choice==0){
    a = 6;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 6;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 6;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 6;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 6;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 6;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 6;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 6;
    num2 = 1000*a +100*b + 10*c + d;
  }
  track++;
  Delay();
  break;
} 

return;
}


void row3(){
  
*rowa = 0x04;
switch(*colc){
  

  case 0x01:
  
  if(track==0 && choice==0){
    a = 7;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 7;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 7;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 7;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 7;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 7;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 7;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 7;
    num2 = 1000*a +100*b + 10*c + d;
  }
  track++;
  Delay();
  break;

  case 0x02:
  
if(track==0 && choice==0){
    a = 8;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 8;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 8;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 8;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 8;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 8;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 8;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 8;
    num2 = 1000*a +100*b + 10*c + d;
  }
track++;
Delay();
  break;

  case 0x04:
  
  if(track==0 && choice==0){
    a = 9;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 9;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 9;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 9;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 9;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 9;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 9;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 9;
    num2 = 1000*a +100*b + 10*c + d;
  }
track++;
Delay();
  break;

 case 0x08:
 choice =1;
 track=0;
 break;


}
  
return;

}

void row4(){
*rowa = 0x08;

switch(*colc){
  
  case 0x02:
  
  if(track==0 && choice==0){
    a = 0;
    num1 = a;
  }
  if(track==1 && choice==0){
    b = 0;
    num1 = a*10+b;
  }

  if(track==2 && choice==0){
    c = 0;
    num1 = 100*a + 10*b +c;
  }
  if(track==3 && choice==0){
    d = 0;
    num1 = 1000*a + 100*b + 10*c + d;

  }

  if(track==0 && choice!=0){
    a = 0;
    num2 = a;
  }
   if(track==1 && choice!=0){
    b = 0;
    num2 = a*10 +b;
  }
   if(track==2 && choice!=0){
    c = 0;
    num2 = 100*a +10*b +c;
  }
   if(track==3 && choice!=0){
    d = 0;
    num2 = 1000*a +100*b + 10*c + d;
  }

  track++;
  Delay();
  break;

  case 0x04:
  if(num2!=0){
    start =1;
  }  
  break;
}

return;
}


void loop() {
  
//Serial.println(*colc);
if(choice==1){
  result = num1 * num2;
}

  
  if(start==1){
    //for 5 or more digits
     
  if(result/10000!=0){
    Echeck =1;
    *outk = 0x00;
    *outf = 121;
    
  }
  // for 4 digits
  if(Echeck!=1){
    if(result/1000!=0){
      resultSize = 4;
    a = result/1000;
    b = result/100;
    b = b%10;
    c = result/10;
    c = c%10;
    d = result%10;
    }
    // for 3 digits
    if(result/100!=0 && result/1000==0){
      resultSize =3;
      a = result/100;
      b = result/10;
      b = b%10;
      c = result%10;
    }

// for 2 digits
    if(result/100==0){
      resultSize = 2;
      a = result / 10;
      b = result % 10;
      // Serial.println(result);

    }
    // for 1 digit
    if(result/10==0){
      resultSize=1;
     a = result;
    
    }
    if(resultSize >=0){
switch(a){
  
      case 0:
      *outk = 254;
      *outf = 0x3F;
      temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);

      break; 

      case 1:
      *outk = 254;
      *outf = 0x06;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 2:
      *outk = 254;
      *outf = 0x5B;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 3:
      *outk = 254;
      *outf = 0x4F;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 4:
      *outk = 254;
      *outf = 0x66;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 5:
      *outk = 254;
      *outf = 0x6D;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 6:
      *outk = 254;
      *outf = 0x7D;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
      
      case 7:
      *outk = 254;
      *outf = 0x7D;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 8:
      *outk = 254;
      *outf = 0x7F;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 9:
      *outk = 254;
      *outf = 0x67;
       temp=*outf;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
    }
    }
// switch b
if(resultSize>=2){
switch(b){
      case 0:

      *outk = 253;
      *outf = 0x3F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);

      break; 

      case 1:
      *outk = 253;
      *outf = 0x06;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 2:
      *outk = 253;
      *outf = 0x5B;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 3:
      *outk = 253;
      *outf = 0x4F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 4:
      *outk = 253;
      *outf = 0x66;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 5:
      *outk = 253;
      *outf = 0x6D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 6:
      *outk = 253;
      *outf = 0x7D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
      
      case 7:
      *outk = 253;
      *outf = 0x7D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 8:
      *outk = 253;
      *outf = 0x7F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 9:
      *outk = 253;
      *outf = 0x67;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
    }
}
// switch c 
if(resultSize>=3){
switch(c){
      case 0:

      *outk = 251;
      *outf = 0x3F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);

      break; 

      case 1:
      *outk = 251;
      *outf = 0x06;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 2:
      *outk = 251;
      *outf = 0x5B;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 3:
      *outk = 251;
      *outf = 0x4F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 4:
      *outk = 251;
      *outf = 0x66;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 5:
      *outk = 251;
      *outf = 0x6D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 6:
      *outk = 251;
      *outf = 0x7D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
      
      case 7:
      *outk = 251;
      *outf = 0x7D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 8:
      *outk = 251;
      *outf = 0x7F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 9:
      *outk = 251;
      *outf = 0x67;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
    }
}
//
if(resultSize==4){
switch(d){
      case 0:

      *outk = 247;
      *outf = 0x3F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);

      break; 

      case 1:
      *outk = 247;
      *outf = 0x06;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 2:
      *outk = 247;
      *outf = 0x5B;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 3:
      *outk = 247;
      *outf = 0x4F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 4:
      *outk = 247;
      *outf = 0x66;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 5:
      *outk = 247;
      *outf = 0x6D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 6:
      *outk = 247;
      *outf = 0x7D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
      
      case 7:
      *outk = 247;
      *outf = 0x7D;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 8:
      *outk = 247;
      *outf = 0x7F;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;

      case 9:
      *outk = 247;
      *outf = 0x67;
      for(int i=0;i<100;i++);
      *outk = 255;
      *outf = 0x00;
      for(int i=0;i<100;i++);
      break;
    }
}

  
  }
  
}
  
row1();
row2();
row3();
row4();
  
}