填空题

[说明] 假设二叉树采用链式存储方式存储，编写一个后序遍历二叉树的非递归方式。 Void postorder (btree * B) { btree * stack [m0] , *p; int tag [m0], top =0; p=b; do { while (p! =NULL) { top+ +; (1) tag [top] =0; p =p- ＞left; } if (top ＞0) { (2) if (tag[top3 = =1) { (3) print ("%d", p- ＞data); } if(top＞0) { (4) tag [top] = 1; } } } while (p! = NULL && top ! =0) }