二叉非递归的中序遍历（递归创建）

二叉链表的存储结构，创建二叉树，利用栈实现非递归中序遍历。

#include<stdio.h> #include<malloc.h> #include<stdlib.h> #define MaxSize 100 typedef struct BiNode { int data; BiNode *lchild; BiNode *rchild; }BiNode, *BiTree; typedef struct { BiNode *a[MaxSize]; int top; }SqStack; int TreeCreated = 0; int CreatTree(BiTree *T); void NrInOrder(BiTree T); void Push(SqStack *s, BiNode *x); BiNode *Pop(SqStack *s); int main() { int choice = 0, flag; int leave = 0; BiNode *BT; printf("/n----------利用栈实现非递归遍历演示程序-----------/n"); do { printf("1.创建一个二叉树，按先序遍历结果输入，空用0表示/n"); printf("2.中序遍历二叉树，非递归方式遍历二叉树/n"); printf("0.Quit/n"); printf("-----Input your selection:"); scanf("%d", &choice); switch(choice) { case 1: if(TreeCreated) { printf("sorry, the tree has been already created!/n"); break; } printf("please put in number:/n"); flag = CreatTree(&BT); if(flag == 1) { printf("ok, the tree named BT is created/n"); TreeCreated = 1; } break; case 2: printf("In NrOrder:"); NrInOrder(BT); break; case 0: leave = 1; break; } }while(!leave); printf("thanks for using, byebye!/n"); return 0; } int CreatTree(BiTree *T) { int ch = 0; scanf("%d", &ch); if(ch == 0) (*T) = NULL; else { (*T) = (BiTree) malloc (sizeof(BiNode)); (*T)->data = ch; CreatTree(&(*T)->lchild); CreatTree(&(*T)->rchild); } return 1; } void NrInOrder(BiTree T) { SqStack s; BiNode *p; s.top = 0; Push(&s, T); while(s.top != 0) { while(s.a[s.top] != NULL) { p = s.a[s.top]; Push(&s, p->lchild); } p = Pop(&s); if(s.top != 0) { p = Pop(&s); printf("%3d", p->data); Push(&s, p->rchild); } } printf("/n"); } void Push(SqStack *s, BiNode *x) { if(s->top == MaxSize) printf("/nstack overflow!"); else { s->top++; s->a[s->top] = x; } } BiNode *Pop(SqStack *s) { BiNode *x; if(s->top == 0) { printf("/n stack underflow!"); return NULL; } else { x = s->a[s->top]; s->top--; return (x); } }