(2)先根次序周游 算法6.2先根次序周游的递归表示 procedure PREORDER(T) //T是一棵二元树。T的每个结点有三个信 息段：LCHILD,DATA,RCHILD// ifT≠0then call VISIT(T) cal1 PREORDER(LCHILD(T)) cal1 PREORDER(RCHILD(T)) endif end preORDER⑵先根次序周游 算法6.2 先根次序周游的递归表示 procedure PREORDER(T) //T是一棵二元树。T的每个结点有三个信 息段:LCHILD, DATA,RCHILD// if T≠0 then call VISIT(T) call PREORDER(LCHILD(T)) call PREORDER(RCHILD(T)) endif end PREORDER