check whether s [ i ] is a character or a integer between 0 to 9 and compute its equivalent BCD
if ( s [ i ] >= 47 && s [ i ] <= 52 ) cout << bitset < 4 > ( s [ i ] ) << " ▁ " ; else cout << bitset < 4 > ( s [ i ] - 55 ) << " ▁ " ; } }