Various traversal of binary tree

/* Two fork Tree of various traversal, first, middle, post, hierarchy, recursive and non-recursive. */#include <iostream> #include <stack> #include <queue>using namespace std;typedef struct bi_node{cha R data;struct Bi_node *lchild,*rchild;}  bit_node,*bit_tree;/* because your bitree type is itself a pointer type that points to a struct, a deep copy does not occur in the process of passing parameters if you pass an object argument and there is a pointer inside the object, a shallow copy will occur if you do not add a reference. But when this happens, the two pointers point to the same piece of memory, so you have to write your own copy constructor to make a deep copy, but if you add a reference, he will not call the copy constructor to construct the temporary object, but instead directly reference your argument object so that the pointer in the class will not collapse */void Creat_    Node (bit_tree &t)//does not add &amp, and does not assign a value to the pointer, thus becoming the wild pointer {char data; Cin>>data;if (data = = ' # ') {T = NULL;} Else{t = (bit_tree) malloc (sizeof (Bi_node)); T->data = Data;creat_node (t->lchild); Creat_node (T->rchild);}}    void Print_node (Bit_tree T) {if (T->data! = ' # ') {cout<<t->data<< "";        }}void Pref_order (Bit_tree t)//First order traversal recursive root-left-right {if (t! = NULL) {print_node (t);    Pref_order (T->lchild);p Ref_order (t->rchild); }}void _pref_order (Bit_tree T)//First Order traversal non-recursive {stack<bit_tree> s;    Bit_tree p = T;  while (P | |!s.empty ()) {  if (P! = NULL) {s.push (P);cout<<p->data<< "";p = p->lchild;            } else{p=s.top ();    S.pop ();p = P->rchild;}      }}void In_order (Bit_tree t)//middle order traversal recursive left-root-right {if (t! = NULL) {in_order (t->lchild);p Rint_node (t);    In_order (T->rchild); }}void _in_order (Bit_tree T)//Middle sequence traverse non-recursive {stack<bit_tree> s;    Bit_tree p = T;        while (P | |!s.empty ()) {if (P! = NULL) {s.push (P);//cout<<p->data<< "";p = P->lchild;}            else{p=s.top ();cout<<p->data<< "";    S.pop ();p = P->rchild;} }}void Post_order (Bit_tree t)//post-traversal recursive left-right-root {if (T! = NULL) {post_order (t->lchild);p Ost_order (t->rchild          );p Rint_node (T);    }}typedef struct bit_node_post{char tag; Bit_tree Bit_tree;} *_bit_node_post;void _post_order (Bit_tree T)//post-traversal non-recursive {stack<_bit_node_post> s;    Bit_tree p = T;_bit_node_post bt;   while (P | |,!s.empty ()) {while (P! = NULL) {         BT = (_bit_node_post) malloc (sizeof (bit_node_post));        Bt->tag = ' L '; bt->bit_tree = P;s.push (BT);p = P->lchild;}            while (!s.empty () && ((S.top ())->tag = = ' R ')) {BT = S.top (); S.pop ();cout<<bt->bit_tree->data<< "";}    if (!s.empty ()) {BT = S.top (); bt->tag = ' R ';p = Bt->bit_tree;p = P->rchild;} }}void Level_order (Bit_tree T)//Hierarchical traversal (good) one layer, from left to right {queue<bit_tree> q;        Bit_tree p = T;q.push (P); while (!q.empty ()) {p = Q.front (); cout<<p->data<< ""; Q.pop (); if (p->lchild! = NULL) {Q.push (p->lchild);} if (p->rchild! = NULL) {Q.push (p->rchild);}}}  int main () {Bit_tree T; The pointer to the root node is initialized, and the following T is not used & referenced.    Creat_node (t);cout<< "First order traversal (recursion)" <<endl;pref_order (t);    cout<<endl; cout<< "Sequential traversal (non-recursive)" <<endl;_pref_order (T);cout<<endl;cout<< "Middle sequence Traversal (recursive)" <<endl;in_    Order (T); cout<<endl;cout<< "Middle sequence traversal (non-recursive)" &LT;&LT;endl;_in_order (t);cout<<endl;cout<< "post-sequential traversal (recursion)" <<endl;post_order (t); cout<<endl;cout<< "post-traversal (non-recursive)" <<endl;_post_order (T);cout<<endl;cout<< "Hierarchical traversal" < <endl;level_order (T); Cout<<endl;return 0;}

Bitree T-Define Bitree An instance object: T; Bitree &t, a reference to an instance object that defines Bitree, is an alias for an already defined object and needs to be initialized;/* Excerpt from << high quality C++/C Programming Guide >> Reference is a concept in C + +. Beginners tend to confuse references with pointers. In the program, N is a reference to M (reference), and M is the quoted (referent).    int m;    int &n = M;n is equivalent to M's alias (nickname), and any operation on N is an operation on M. For example, someone named Wang Xiaomao, whose nickname is "Sanmao". Say "Sanmao" how how, in fact is to Wang Xiao judge. So n is neither a copy of M nor a pointer to M, in fact N is M itself. */bitree *t, a pointer to an instance object that defines Bitree, points to an instance object; Code reference: Bitree T; Bitree &t = T; Bitree *t = &T; & is the address to take.

Various traversal of binary tree