state transitions 0 takes to q1 , 1 takes to q3
if ( s [ i ] == '0' ) q1 ( s , i + 1 ) ; else q3 ( s , i + 1 ) ; } void q0 ( string s , int i ) { cout << " q0 - > " ; if ( i == s . length ( ) ) { cout << " NO ▁ STRNEWLINE " ; return ; }