• 广度优先遍历

//广度优先遍历
void breadthFirst(Node* &bt){queue<Node*> que;Node* BT = bt;que.push(BT);while (!que.empty()){BT = que.front();que.pop();printf("%c", BT->data);if (BT->lchild)que.push(BT->lchild);if (BT->rchild)que.push(BT->rchild);}
}复制代码

• 深度优先遍历

• V-访问节点
• L-遍历左子树
• R-遍历右子树

//从左向右前中后递归遍历
void leftPreOrder(Node *bt)
{if (bt){printf("%c", bt->data);leftPreOrder(bt->lchild);leftPreOrder(bt->rchild);}
}void leftInOrder(Node *bt)
{if (bt){leftInOrder(bt->lchild);printf("%c", bt->data);leftInOrder(bt->rchild);}
}void leftPostOrder(Node *bt)
{if (bt){leftPostOrder(bt->lchild);leftPostOrder(bt->rchild);printf("%c", bt->data);}
}复制代码

节点定义：typedef struct BiNode{int data;struct BiNode * lchild;struct BiNode * rchild;
}BiNode,*BiTree;前序遍历：void preOrderBiTree(BiNode * root){if(root == NULL)return;BiNode * node = root;stack<BiNode*> nodes;while(node || !nodes.empty()){while(node != NULL){nodes.push(node);printf("%d",node->data);node = node -> lchild;}node = nodes.top();//回溯到父节点nodes.pop();node = node -> rchild;}
}复制代码

void inOrderBinaryTree(BiNode * root){if(root == NULL)return;BiNode * node = root;stack<BiNode*> nodes;while(node || !nodes.empty()){while(node != NULL){nodes.push(node);node = node ->lchild;}node = nodes.top();printf("%d ",node ->data);nodes.pop();node = node ->rchild;}
}复制代码

void PostOrderS(Node *root) {Node *p = root, *r = NULL;stack<Node*> s;while (p!=NULL || !s.empty()) {if (p!=NULL) {//走到最左边s.push(p);p = p->left;}else {p = s.top();if (p->right!=NULL && p->right != r)//右子树存在，未被访问p = p->right;else {s.pop();visit(p->val);r = p;//记录最近访问过的节点p = NULL;//节点访问完后，重置p指针}}//else}//while
}复制代码

/*二叉树节点*/
typedef struct node
{char data;struct node *lchild, *rchild;
}Node;/*二叉树栈*/
typedef struct
{int top;//指向二叉树节点指针的指针struct node* data[MAX];bool   isNode[MAX];
}SqStack;void push(SqStack *&s, Node *bt, bool isNode = true)
{if (s == NULL)return;if (s->top == MAX - 1){printf("栈满，不能再入栈");}else{s->top++;s->data[s->top] = bt;s->isNode[s->top] = isNode;}
}Node* pop(SqStack *&s)
{if (s->top == -1){printf("栈空，不能出栈");}else{Node* temp;temp = s->data[s->top];s->top--;return temp;}
}bool topIsNode(SqStack *&s){if (s->top != -1)return s->isNode[s->top];return false;
}//从左向右前中后非递归遍历
void leftPreOrder(Node *bt)
{Node *BT = bt;bool isNode = false;push(s, BT, isNode);while (!EmptyStack(s)){isNode = topIsNode(s);BT = pop(s);if (isNode){printf("%c", BT->data);}else{if (BT->rchild != NULL)push(s, BT->rchild, false);if (BT->lchild != NULL)push(s, BT->lchild, false);push(s, BT, true);}     }
}void leftSimPreOrder(Node *bt)
{Node *BT = bt;push(s, BT);while (!EmptyStack(s)){BT = pop(s);printf("%c", BT->data);if (BT->rchild != NULL)push(s, BT->rchild);if (BT->lchild != NULL)push(s, BT->lchild);}
}void leftInOrder(Node *bt)
{Node *BT = bt;bool isNode = false;push(s, BT, isNode);while (!EmptyStack(s)){isNode = topIsNode(s);BT = pop(s);if (isNode){printf("%c", BT->data);}else{if (BT->rchild != NULL)push(s, BT->rchild, false);push(s, BT, true);if (BT->lchild != NULL)push(s, BT->lchild, false);}}
}void leftPostOrder(Node *bt)
{Node *BT = bt;bool isNode = false;push(s, BT, isNode);while (!EmptyStack(s)){isNode = topIsNode(s);BT = pop(s);if (isNode){printf("%c", BT->data);}else{push(s, BT, true);if (BT->rchild != NULL)push(s, BT->rchild, false);if (BT->lchild != NULL)push(s, BT->lchild, false);}}
}复制代码