#include<stdio.h> #include<stdlib.h> typedef struct TreeNode { char data; struct TreeNode* lch; struct TreeNode* rch; }TreeNode; typedef struct QueueNode { TreeNode* data; struct QueueNode* pre; struct QueueNode* next; }QueueNode; void createTree(TreeNode** T, char* data, int* index) { char ch; ch = data[*index]; *index += 1; if (ch == '#') { *T = NULL; } else { *T = (TreeNode*)malloc(sizeof(TreeNode)); (*T)->data = ch; createTree(&((*T)->lch), data, index); createTree(&((*T)->rch), data, index); } } void preOrder(TreeNode* T) { if (T == NULL) { return; } else { printf("%c ", T->data); preOrder(T->lch); preOrder(T->lch); } } int main(int argc,char* argv[]) { TreeNode* T; int index = 0; createTree(&T, argv[1], &index); preOrder(T); printf("\n"); return 0; }检查错误（编译器vs）

你的程序中存在一个小错误，即在 preOrder 函数中，递归调用时应该是 preOrder(T->rch)，而不是 preOrder(T->lch)。下面是修改后的代码：

#include<stdio.h> 
#include<stdlib.h> 

typedef struct TreeNode { 
    char data; 
    struct TreeNode* lch; 
    struct TreeNode* rch; 
}TreeNode; 

typedef struct QueueNode { 
    TreeNode* data; 
    struct QueueNode* pre; 
    struct QueueNode* next; 
}QueueNode; 

void createTree(TreeNode** T, char* data, int* index) { 
    char ch; 
    ch = data[*index]; 
    *index += 1; 
    if (ch == '#') { 
        *T = NULL; 
    } 
    else { 
        *T = (TreeNode*)malloc(sizeof(TreeNode)); 
        (*T)->data = ch; 
        createTree(&((*T)->lch), data, index); 
        createTree(&((*T)->rch), data, index); 
    } 
} 

void preOrder(TreeNode* T) { 
    if (T == NULL) { 
        return; 
    } 
    else { 
        printf("%c ", T->data); 
        preOrder(T->lch); 
        preOrder(T->rch); 
    } 
} 

int main(int argc,char* argv[]) { 
    TreeNode* T; 
    int index = 0; 
    createTree(&T, argv[1], &index); 
    preOrder(T); 
    printf("\n"); 
    return 0; 
}

修改后的程序应该可以正常编译运行了。