const byte
rows = 8,
columns = 8,
rowpins [ rows ] = { 23, 25, 27, 29, 31, 33, 35, 37 },
columnpins [ columns ] = { 13, 12, 11, 10, 9, 8, 7, 6 }
;

char 
letter[8] = "abcdefgh",
number[8] = "87654321";


boolean
currentState [ rows ] [ columns ],
previousState [ rows ] [ columns ]
;

void initialise ()
{
  Serial.println ( "Board initialising\n" );
  delay ( 2000 );
  Serial.println ( " ... \n" );
  delay ( 500 );
  Serial.println ( " ... " );
  
  for ( byte n = 0; n < rows; n ++ ) pinMode ( rowpins [ n ], INPUT_PULLUP );
  for ( byte n = 0; n < columns; n ++ ) pinMode ( columnpins [ n ], INPUT_PULLUP );
  
  for ( byte r = 0; r < rows; r ++ )
  {
    pinMode ( rowpins [ r ], OUTPUT ); digitalWrite ( rowpins [ r ], LOW );
    delayMicroseconds ( 20 );
    for ( byte c = 0; c < columns; c ++ )
    {
      previousState [ r ] [ c ] = currentState [ r ] [ c ];
      currentState [ r ] [ c ] = digitalRead ( columnpins [ c ] );
    }
    pinMode ( rowpins [ r ], INPUT_PULLUP );
  }
  
  delay ( 500 );
  Serial.println ( "\nCurrent Layout :\n");
  for ( byte r = 0; r < rows; r ++ )
  {
    for ( byte c = 0; c < columns; c ++ )
    {
      Serial.print ( "\t" );

      Serial.print ( currentState [ r ] [ c ] );
    }
    Serial.println ();
  }
  Serial.println();
  Serial.println();
  Serial.println();
  delay(2000);
  Serial.println ( "\nPrevious Layout :\n");
  for ( byte r = 0; r < rows; r ++ )
  {
    for ( byte c = 0; c < columns; c ++ )
    {
      Serial.print ( "\t" );
      Serial.print ( previousState [ r ] [ c ] );
    }
    Serial.println ();
  }
  
  delay(2000);
}

void setup ()
{
  Serial.begin ( 115200 );
  delay ( 2000 );
  for (byte i = 0; i < 8; i++) {
    for (byte j = 0; j < 8; j++) {
      currentState[i][j] = 1;
      previousState[i][j] = 1;
    }
  }

}

void loop()
{
  initialise();
  for (byte i = 0; i < 8; i++) {
    for (byte j = 0; j < 8; j++) {
      if (currentState[i][j] != previousState[i][j]){
        Serial.println(letter[j]);
        Serial.println(number[i]);
        Serial.println(letter[j] += number[i]);
      }
    }
  }
}