C++之树的层序遍历和深度优先遍历（先序遍历）（14）---《那些奇怪的算法》

#include <iostream>
#include <string>
#include <stack>
#include <queue>
using namespace std;
typedef struct QNode{
struct QNode* left;
struct QNode* right;
int data;
QNode(int data, QNode* left=NULL, QNode* right=NULL){
this->data = data;
this->left = left;
this->right = right;
}
};
void dfs(QNode* root){
if (root != NULL) cout << root->data << endl;
else return;

if (root->left) dfs(root->left);
if (root->right) dfs(root->right);
}
void dfs_iter(QNode* root){
stack<QNode*> sta;
sta.push(root);
QNode* temp = NULL;
while (!sta.empty()){
temp = sta.top();
sta.pop();
if (temp) cout << temp->data << endl;
if (temp->right) sta.push(temp->right);
if (temp->left) sta.push(temp->left);
}
}

void bfs_iter(QNode* root){
queue<QNode*> que;
que.push(root);
QNode* temp = NULL;
while (!que.empty()){
temp = que.front();
que.pop();
if (temp != NULL) cout << temp->data << endl;
if (temp->left) que.push(temp->left);
if (temp->right) que.push(temp->right);
}
}
int main(){
QNode root(1);
QNode l1_left(2);
QNode l1_right(3);

QNode l12_left(4);
QNode l12_right(5);

QNode l21_left(6);
QNode l22_right(7);

root.left = &l1_left;
root.right = &l1_right;

l1_left.left = &l12_left;
l1_left.right = &l12_right;

l1_right.left = &l21_left;
l1_right.right = &l22_right;

dfs_iter(&root);
cout << endl;
bfs_iter(&root);
return 0;
return 0;
}