text: Driver Code
code: int main ( ) { string tree = " ( 0(5(6 ( ) ( ) ) ( 4 ( ) " " ( 9 ( ) ( ) ) ) ) ( 7(1 ( ) ( ) ) ( 3 ( ) ( ) ) ) ) " ; int k = 2 ; int i = 0 ; cout << productAtKthLevel ( tree , k , i , 0 ) ; return 0 ; }