二叉树前序、中序和后序非递归遍历的方法

/*********************************************************** Author: vison Email : vison0300@163.com Date : 2010-03-19 ***********************************************************/ #include <stdio.h> #include <malloc.h> #include <string.h> typedef int btData; typedef struct btNode { btData data; btNode *lchild, *rchild; }BinTree; void DeleteBinTree(BinTree* bt) { if (bt) { DeleteBinTree(bt->lchild); DeleteBinTree(bt->rchild); free(bt); } } bool _isdigit(int d) { return (d >= 0 && d <= 9); } BinTree* CreateBinTree(btData** ds) { if (!_isdigit(**ds)) { (*ds)++; return 0; } BinTree* pNode = (BinTree*)malloc(sizeof(BinTree)); if (pNode) { pNode->data = *(*ds)++; pNode->lchild = 0; pNode->rchild = 0; pNode->lchild = CreateBinTree(ds); pNode->rchild = CreateBinTree(ds); } return pNode; } //Stack------------------------------------------------------------------------ typedef btNode* stNode; struct Stack { stNode* buf; int top; int size; }; void InitStack(Stack& s, int sz) { int i = sizeof(stNode) * sz; s.buf = (stNode*)malloc(i); s.top = 0; s.size = sz; char* p = (char*)s.buf; while (i > 0) { p[--i] = 0; } } bool Push(Stack& s, stNode n) { if (s.top >= s.size) { return false; } s.buf[s.top++] = n; return true; } bool Pop(Stack& s, stNode& n) { if (s.top == 0) { return false; } n = s.buf[--s.top]; return true; }; stNode StackTop(Stack& s) { if (s.top <= 0)return s.buf[0]; return s.buf[s.top - 1]; } bool StackEmpty(Stack& s) { return (s.top == 0); } void DeleteStack(Stack& s) { free(s.buf); } ////////////////////////////////////////////////////////// //中序遍历 void InOrderTraverse(BinTree* bt) { Stack s; InitStack(s, 10); stNode p = bt; while (p || !StackEmpty(s)) { if (p) { Push(s, p); p = p->lchild; } else { Pop(s, p); printf("%d,", p->data); p = p->rchild; } } DeleteStack(s); }; //前序遍历 void PreOrderTraverse(BinTree* bt) { Stack s; InitStack(s, 10); stNode p = bt; while (p || !StackEmpty(s)) { if (p) { printf("%d,", p->data); Push(s, p); p = p->lchild; } else { Pop(s, p); p = p->rchild; } } DeleteStack(s); }; //后序遍历 void PostOrderTraverse(BinTree* bt) { Stack s, t; InitStack(s, 10); InitStack(t, 10); stNode r = 0; stNode p = bt; while (p || !StackEmpty(s)) { if (p) { Push(s, p); if (p->rchild)Push(t, p->rchild); p = p->lchild; } else { p = StackTop(s); r = StackTop(t); if (p->rchild == r) { Pop(t, r); Push(t, p);//临时堆栈保存非叶子节点 p = r; continue; } Pop(s, p); printf("%d,", p->data); if (p == r) { p = 0; Pop(t, r); } else { p = p->rchild; } } } DeleteStack(s); } int main(int argc, char* argv[]) { btData ds[] = {0,1,3,'x','x',4,'x','x',2,5,'x','x',6,'x','x'}; btData* p = ds; BinTree* root = CreateBinTree(&p); printf("InOrderTraverse: "); InOrderTraverse(root); printf("/r/nPreOrderTraverse: "); PreOrderTraverse(root); printf("/r/nPostOrderTraverse: "); PostOrderTraverse(root); while (getchar() != 'q'); return (0); }