szjy_6_树_018

阅读代码，程序输出是（ ）。

#include <iostream>
#include <queue>
using namespace std;

struct Node {
int value;
Node* left = nullptr;
Node* right = nullptr;
};

void print(Node* root) {
queue<Node*> q;
q.push(root);
while (!q.empty()) {
Node* p = q.front();
q.pop();
cout << p->value << ' ';
if (p->left) q.push(p->left);
if (p->right) q.push(p->right);
}
}

int main() {
Node a{8}, b{4}, c{12}, d{2}, e{6}, f{10};
a.left = &b;  a.right = &c;
b.left = &d;  b.right = &e;
c.left = &f;
print(&a);
}

{{ select(1) }}

• 2 4 6 8 10 12
• 8 4 12 2 6 10
• 2 6 4 10 12 8
• 8 4 2 6 12 10