二叉树建立、存储、遍历

#include <iostream>using namespace std;struct BTreeNode{char val;BTreeNode *lf;BTreeNode *rf;};void init(BTreeNode* &p)   //指针引用{char ch;cin>>ch;if(ch != '!'){p = new BTreeNode;p->val = ch;init(p->lf);init(p->rf);}else{p = NULL;}}void pre(BTreeNode *p){if(p){cout<<p->val;pre(p->lf);pre(p->rf);}}void ino(BTreeNode *p){if(p){ino(p->lf);cout<<p->val;ino(p->rf);}}void pro(BTreeNode *p){if(p){pro(p->lf);pro(p->rf);cout<<p->val;}}int main(){BTreeNode *p;init(p);pre(p);cout<<endl;ino(p);cout<<endl;pro(p);cout<<endl;return 0;}

运行结果如下：