Question

我用C语言写了二进制搜索树，哪个数据是字符串，当我尝试输入数据时遇到问题。

错误显示在第14行，我认为root->data为NULL导致它，但我不知道如何解决。

这是我的代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct Node {
    Node *parent;
    Node *left;
    Node *right;
    char *data;
};
Node *insert(Node *root, char *data) {
    if (root == NULL) {
        Node *tmp;
        tmp = (Node *)malloc(sizeof(Node));
        root->data = data;    // <--- Line 14
        tmp -> left = tmp -> right = NULL;
        return tmp;
    }
    if (strcmp(data, root->data) > 0) {
        root -> right = insert(root->right, data);
    } else if (strcmp(data, root->data) < 0) {
        root -> left = insert(root->left, data);
    }
    return root;
}

void Print(Node *root){
    if (root == NULL) return;
    Print(root->left);
    printf("%s\n", root->data);
    Print(root->right);
}

int main() {
    Node *root = NULL;
    char input[21];
    while (scanf("%s", input) != EOF) {
        root = insert(root, input);
    }
    Print(root);
    return 0;
}

Answer 1

在你的功能中：

Node *insert(Node *root, char *data) {
    if (root == NULL) {
        Node *tmp;            // is this really needed?
        tmp = (Node *)malloc(sizeof(Node)); // did your mean root = malloc(..) ?
        root->data = data;    // <--- root is always NULL, from test above

/* ... */

线程1：EXC_BAD_ACCESS

1 个答案: