implemented utility function: bitboard::utils::notation_from_square_number

engine/src/bitboard/utils.rs

@@ -11,8 +11,19 @@ pub fn pop_msb(value: &mut u64) -> usize {
   return idx;
 }
 
+const RANK_NUMBERS: [char; 8] = ['1', '2', '3', '4', '5', '6', '7', '8'];
+const FILE_LETTERS: [char; 8] = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
 pub fn notation_from_square_number(sq: u8) -> String {
-  return String::new();
+  let row = sq / 8;
+  let col = sq % 8;
+  let mut notation = String::new();
+
+  let row_not = RANK_NUMBERS[row as usize];
+  let col_not = FILE_LETTERS[col as usize];
+
+  notation.push(col_not);
+  notation.push(row_not);
+  return notation;
 }