state transitions 0 takes to q4 , 1 takes to q2
if ( s [ i ] == '0' ) q4 ( s , i + 1 ) ; else q2 ( s , i + 1 ) ; } void q3 ( string s , int i ) { cout << " q3 - > " ; if ( i == s . length ( ) ) { cout << " YES ▁ STRNEWLINE " ; return ; }