树-链式存储

#include<stdio.h>
#include<malloc.h>

struct BTNode{
    char data;
    struct BTNode *pLchild;
    struct BTNode *pRchild;
};

struct BTNode * CreateBTree();
void PreTraverse(struct BTNode * pT);
void CenterTraverse(struct BTNode * pT);
void LastTraverse(struct BTNode * pT);

int main(void){
    struct BTNode *pT = CreateBTree();
    
    PreTraverse(pT);    //先序
    CenterTraverse(pT); //中序
    LastTraverse(pT);   //后序
    
    return 0;
}

//前序遍历  先根  再左  再右
void PreTraverse(struct BTNode * pT){
    if(pT!=NULL){
        printf("%c\n",pT->data);
        if(pT->pLchild!=NULL){
            PreTraverse(pT->pLchild);
        }
        if(pT->pRchild!=NULL){
            PreTraverse(pT->pRchild);
        }
    }
}

//中序遍历  先左  再根  再右
void CenterTraverse(struct BTNode * pT){
    if(pT!=NULL){
        if(pT->pLchild!=NULL){
            CenterTraverse(pT->pLchild);
        }    
        printf("%c\n",pT->data);
        if(pT->pRchild!=NULL){
            CenterTraverse(pT->pRchild);
        }
    }
}
//后序遍历  先左  再右  再根
void LastTraverse(struct BTNode * pT){
    if(pT!=NULL){
        if(pT->pLchild!=NULL){
            LastTraverse(pT->pLchild);
        }    
        if(pT->pRchild!=NULL){
            LastTraverse(pT->pRchild);
        }
        printf("%c\n",pT->data);
    }
}

//创建一颗链式树
struct BTNode * CreateBTree(void){
    struct BTNode *pA = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode *pB = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode *pC = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode *pD = (struct BTNode *)malloc(sizeof(struct BTNode));
    struct BTNode *pE = (struct BTNode *)malloc(sizeof(struct BTNode));
    pA->data = ‘A‘;
    pA->data = ‘B‘;
    pA->data = ‘C‘;
    pA->data = ‘D‘;
    pA->data = ‘E‘;
    
    pA->pLchild = pB;
    pA->pRchild = pC;
    pB->pLchild = pB->pRchild = NULL;
    pC->pLchild = pD;
    pC->pRchild = NULL;
    pD->pLchild = NULL;
    pD->pRchild = pE;
    pE->pLchild = pE->pRchild = NULL;
    
    return pA;
}