二叉树的遍历

```
//二叉树的三种遍历
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<malloc.h>
#define OK 1
#define ERROR 0
#define OVERFLOW -1
typedef  char TElemType;
typedef int Status ;
typedef struct BiTNode{
    TElemType data;
    struct BiTNode *lchild,*rchild;
}BiTNode,*BiTree;
Status PrintElement(TElemType e){
    printf("%c",e);
    return OK;
}
Status CreateBiTree(BiTree &T){
    TElemType ch;
    scanf("%c",&ch);
    if(ch=='#'){
        T=NULL;
    }else{
        if(!(T=(BiTNode*)malloc(sizeof(BiTNode))))
            exit(OVERFLOW);
        T->data=ch;
        CreateBiTree(T->lchild);
        CreateBiTree(T->rchild);
    }
    return OK;
}
Status PreOrderTraverse(BiTree T,Status (* Visit)(TElemType e)){//先序遍历
    if(T){
        if(Visit(T->data))
            if(PreOrderTraverse(T->lchild,Visit))
                if(PreOrderTraverse(T->rchild,Visit)) return OK;
        return ERROR;
    }else return OK;
}
Status InOrderTraverse(BiTree T,Status (* Visit)(TElemType e)){//中序遍历
    if(T){
        if(InOrderTraverse(T->lchild,Visit))
            if(Visit(T->data))
                if(InOrderTraverse(T->rchild,Visit)) return OK;
        return ERROR;
    }else return OK;
}
Status PostOrderTraverse(BiTree T,Status (* Visit)(TElemType e)){//后序遍历
    if(T){
        if(PostOrderTraverse(T->lchild,Visit))
            if(PostOrderTraverse(T->rchild,Visit))
                if(Visit(T->data))return OK;
        return ERROR;
    }else return OK;
}
int main(){
    BiTree T;
    CreateBiTree(T);
    PreOrderTraverse(T,PrintElement);
    printf("\n");
    InOrderTraverse(T,PrintElement);
    printf("\n");
    PostOrderTraverse(T,PrintElement);
    printf("\n");
    return 0;
}

“`