#include<iostream> #include<queue> using namespace std; struct Node { Node* left; Node* right; char data; }; /* 初始化一棵樹 */ Node* initTree() { Node *root = new Node; Node *b = new Node; Node* c = new Node; Node* d = new Node; Node* e = new Node; Node* f = new Node; root->data = 'a'; c->data = 'c'; b->data = 'b'; d->data = 'd'; e->data = 'e'; f->data = 'f'; root->left = b; root->right = c; b->left = d; b->right = e; c->right = f; c->left = NULL; d->left = e->left = f->left = NULL; d->right = e->right = f->right = NULL; return root; } void printTreebyRow(Node* root) { queue<Node *> storequeue; storequeue.push(root); while(!storequeue.empty()) { int rowcount=0; queue<Node *> showqueue(storequeue); while(!showqueue.empty()) { cout<<showqueue.front()->data; showqueue.pop(); ++rowcount; } cout<<endl;         // 回車 while(rowcount) { if(storequeue.front()->left) storequeue.push(storequeue.front()->left); if(storequeue.front()->right) storequeue.push(storequeue.front()->right); storequeue.pop(); --rowcount; } } } int main() { printTreebyRow(initTree()); return 0; }