Search key in BST : find Node and its parent .
while ( ptr != NULL ) { if ( dkey == ptr -> info ) { found = 1 ; break ; } par = ptr ; if ( dkey < ptr -> info ) { if ( ptr -> lthread == false ) ptr = ptr -> left ; else break ; } else { if ( ptr -> rthread == false ) ptr = ptr -> right ; else break ; } } if ( found == 0 ) printf ( " dkey ▁ not ▁ present ▁ in ▁ tree STRNEWLINE " ) ;