用C++实现二叉树的三种遍历方式

来源：互联网发布：mac版nba2k14突然变卡编辑：程序博客网时间：2024/06/14 03:17

- 非递归实现代码：

#include<stdio.h>#include<stdlib.h>#include"data_structure.h"//创建一棵二叉树BTree create_tree(){    BTree pA = (BTree)malloc(sizeof(BTNode));    BTree pB = (BTree)malloc(sizeof(BTNode));    BTree pD = (BTree)malloc(sizeof(BTNode));    BTree pE = (BTree)malloc(sizeof(BTNode));    BTree pC = (BTree)malloc(sizeof(BTNode));    BTree pF = (BTree)malloc(sizeof(BTNode));    pA->data = 'A';    pB->data = 'B';    pD->data = 'D';    pE->data = 'E';    pC->data = 'C';    pF->data = 'F';    pA->pLchild = pB;    pA->pRchild = pC;    pB->pLchild = pD;    pB->pRchild = pE;    pD->pLchild = pD->pRchild = NULL;    pE->pLchild = pE->pRchild = NULL;    pC->pLchild = pF;    pC->pRchild = NULL;    pF->pLchild = pF->pRchild = NULL;       return pA;}/*前序遍历的非递归实现*/void pre_traverse(BTree pTree){    PSTACK stack = create_stack();  //创建一个空栈    BTree node_pop;                 //用来保存出栈节点    BTree pCur = pTree;             //定义用来指向当前访问的节点的指针    //直到当前节点pCur为NULL且栈空时，循环结束    while(pCur || !is_empty(stack))    {        //从根节点开始，输出当前节点，并将其入栈，        //同时置其左孩子为当前节点，直至其没有左孩子，及当前节点为NULL        printf("%c ", pCur->data);        push_stack(stack,pCur);        pCur = pCur->pLchild;        //如果当前节点pCur为NULL且栈不空，则将栈顶节点出栈，        //同时置其右孩子为当前节点,循环判断，直至pCur不为空        while(!pCur && !is_empty(stack))        {            pCur = getTop(stack);            pop_stack(stack,&node_pop);            pCur = pCur->pRchild;                   }    }}/*中序遍历的非递归实现*/void in_traverse(BTree pTree){    PSTACK stack = create_stack();  //创建一个空栈    BTree node_pop;                 //用来保存出栈节点    BTree pCur = pTree;             //定义指向当前访问的节点的指针    //直到当前节点pCur为NULL且栈空时，循环结束    while(pCur || !is_empty(stack))    {        if(pCur->pLchild)        {            //如果pCur的左孩子不为空，则将其入栈，并置其左孩子为当前节点            push_stack(stack,pCur);            pCur = pCur->pLchild;        }        else        {            //如果pCur的左孩子为空，则输出pCur节点，并将其右孩子设为当前节点，看其是否为空            printf("%c ", pCur->data);            pCur = pCur->pRchild;            //如果为空，且栈不空，则将栈顶节点出栈，并输出该节点，            //同时将它的右孩子设为当前节点，继续判断，直到当前节点不为空            while(!pCur && !is_empty(stack))            {                pCur = getTop(stack);                printf("%c ",pCur->data);                   pop_stack(stack,&node_pop);                pCur = pCur->pRchild;            }        }    }}/*后序遍历的非递归实现*/void beh_traverse(BTree pTree){    PSTACK stack = create_stack();  //创建一个空栈    BTree node_pop;          //用来保存出栈的节点    BTree pCur;              //定义指针，指向当前节点    BTree pPre = NULL;       //定义指针，指向上一各访问的节点    //先将树的根节点入栈    push_stack(stack,pTree);      //直到栈空时，结束循环    while(!is_empty(stack))    {        pCur = getTop(stack);   //当前节点置为栈顶节点        if((pCur->pLchild==NULL && pCur->pRchild==NULL) ||             (pPre!=NULL && (pCur->pLchild==pPre || pCur->pRchild==pPre)))        {            //如果当前节点没有左右孩子，或者有左孩子或有孩子，但已经被访问输出，            //则直接输出该节点，将其出栈，将其设为上一个访问的节点            printf("%c ", pCur->data);            pop_stack(stack,&node_pop);            pPre = pCur;        }        else        {            //如果不满足上面两种情况,则将其右孩子左孩子依次入栈            if(pCur->pRchild != NULL)                push_stack(stack,pCur->pRchild);            if(pCur->pLchild != NULL)                push_stack(stack,pCur->pLchild);        }    }}

- 递归实现代码：

#include<stdio.h>#include<stdlib.h>typedef struct BTNode{    char data;    struct BTNode *pLchild;    struct BTNode *pRchild;}BTNode, *BTree;BTree create_tree();void pre_traverse(BTree);void in_traverse(BTree);void beh_traverse(BTree);int main(){    BTree pTree = create_tree();    printf("递归实现前序遍历结果：");    pre_traverse(pTree);    printf("\n");    printf("递归实现中序遍历结果：");    in_traverse(pTree);    printf("\n");    printf("递归实现后序遍历结果：");    beh_traverse(pTree);    printf("\n");    return 0;}BTree create_tree(){    BTree pA = (BTree)malloc(sizeof(BTNode));    BTree pB = (BTree)malloc(sizeof(BTNode));    BTree pD = (BTree)malloc(sizeof(BTNode));    BTree pE = (BTree)malloc(sizeof(BTNode));    BTree pC = (BTree)malloc(sizeof(BTNode));    BTree pF = (BTree)malloc(sizeof(BTNode));    pA->data = 'A';    pB->data = 'B';    pD->data = 'D';    pE->data = 'E';    pC->data = 'C';    pF->data = 'F';    pA->pLchild = pB;    pA->pRchild = pC;    pB->pLchild = pD;    pB->pRchild = pE;    pD->pLchild = pD->pRchild = NULL;    pE->pLchild = pE->pRchild = NULL;    pC->pLchild = pF;    pC->pRchild = NULL;    pF->pLchild = pF->pRchild = NULL;       return pA;}/*前序遍历的递归实现*/void pre_traverse(BTree pTree){    if(pTree)    {        printf("%c ",pTree->data);        if(pTree->pLchild)            pre_traverse(pTree->pLchild);        if(pTree->pRchild)            pre_traverse(pTree->pRchild);       }}/*中序遍历的递归实现*/void in_traverse(BTree pTree){    if(pTree)    {        if(pTree->pLchild)            in_traverse(pTree->pLchild);        printf("%c ",pTree->data);        if(pTree->pRchild)            in_traverse(pTree->pRchild);        }}/*后序遍历的递归实现*/void beh_traverse(BTree pTree){    if(pTree)    {        if(pTree->pLchild)            beh_traverse(pTree->pLchild);        if(pTree->pRchild)            beh_traverse(pTree->pRchild);           printf("%c ",pTree->data);    }}

阅读全文

1 0