在我的链接列表中插入第三个节点时，我的代码似乎超时

Question

我正在学习 C 中的链表。所以我在网上找到了一个项目，可以帮助您体验链表。

您必须创建一个 C 文件，将一些命令作为字符串。 I 插入，P 打印，D 删除，S 搜索，Q 退出。

每当我尝试插入第三个节点并在终端中按回车键时，代码似乎超时。

可能我在某处循环连接了列表，但我无法发现错误。

我将在此感谢您的指导和支持！

    int main(void) 
    {
        // Declare the head of the linked list.
        Node *head = NULL;
        
        char *songName, *artist, *genre;
        
        artist = (char *) malloc(MAX_LENGTH * sizeof (char));
        genre = (char *) malloc(MAX_LENGTH * sizeof (char));
        songName = (char*) malloc(MAX_LENGTH * sizeof (char));
        
        // Announce at the start of the program
        printf("Personal Music Library.\n\n");
        printf("%s", "Commands are I (insert), D (delete), S (search by song name),\n" //I have removed the code for the other commands
               "P (print), Q (quit).\n");
    
        char response;
        
        char input[MAX_LENGTH + 1];
        
        do 
        {
            inputStringFromUser("\nCommand", input, MAX_LENGTH); // Response is the first character entered by user.
            response = toupper(input[0]); // Convert to uppercase to simplify later comparisons.
    
            if (response == 'I') // Insert a song into the linked list and order it alphabeticallly by song name.
            {
                char *promptName = "Song name";
                char *promptArtist = "Artist";
                char *promptGenre = "Genre";
    
                inputStringFromUser(promptName, songName, MAX_LENGTH);
                inputStringFromUser(promptArtist, artist, MAX_LENGTH);
                inputStringFromUser(promptGenre, genre, MAX_LENGTH);
                
                if (!songAlreadyInList(head, songName)) 
                {
                    head = insertNewNode(head, songName, artist, genre);
                } 
                
                else
                {
                    songNameDuplicate(songName);
                }
            }
} while (response != 'Q'); // Delete the entire linked list.

void inputStringFromUser(char *prompt, char *s, int maxStrLength) 
{
    int i = 0;
    char c;

    printf("%s --> ", prompt);
    while (i < maxStrLength && (c = getchar()) != '\n')
        s[i++] = c;
    s[i] = '[=10=]';
}
    Node *insertNewNode(Node *head, char songName[MAX_LENGTH], char artist[MAX_LENGTH], char genre[MAX_LENGTH]) 
    {
        Node *next = head; //to insert first node
        if (head == NULL || strcmp(head -> songName, songName) > 0) 
        {
            Node *insert = (Node *) malloc( sizeof(Node));
            insert -> songName = (char *) malloc(MAX_LENGTH * sizeof(char));
            insert -> artist = (char *) malloc(MAX_LENGTH * sizeof(char));
            insert -> genre = (char *) malloc(MAX_LENGTH * sizeof(char));
            if (insert != NULL) 
            {
                strcpy(insert -> songName, songName);
                strcpy(insert -> artist, artist);
                strcpy(insert -> genre, genre);
                insert -> next = next;
            }
            return insert;
        }
        
        Node *current = head;
        //to insert in the order
        while (current -> next != NULL && strcmp(current -> next -> songName, songName) < 0) 
        {
            current = current -> next;
        }
        
        Node *insert = (Node *) malloc(sizeof (Node));
        insert -> songName = (char *) malloc(MAX_LENGTH * sizeof (char));
        insert -> artist = (char *) malloc(MAX_LENGTH * sizeof (char));
        insert -> genre = (char *) malloc(MAX_LENGTH * sizeof (char));
        if (insert != NULL) 
        {
            strcpy(insert -> songName, songName);
            strcpy(insert -> artist, artist);
            strcpy(insert -> genre, genre);
            insert -> next = next;
        }
        current -> next = insert;
        return head;
    }

Answer 1

这里是修复了以下问题的有效实现：

通过使用单独的函数消除节点创建的重复。这也使得指针调整更容易遵循，因为它现在只是几行代码。
无需强制转换 mallocreturn 的值
检查所有 malloc returns 并处理清理（不泄漏内存）
你更新了head，但是你需要更新head指向的地方（所以需要head的地址）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_LENGTH 10

typedef struct Node Node;
struct Node {
    char *songName;
    Node *next;
};


Node *createNode(char songName[MAX_LENGTH]) {
    Node *newNode = malloc(sizeof(*newNode));
    if(!newNode) {
        printf("malloc failed\n");
        return NULL;
    }

    // simplifies error handling with more attributes
    newNode->songName = NULL;

    newNode->songName = malloc(MAX_LENGTH);
    if(!newNode->songName) {
        printf("malloc failed\n");
        goto err;
    }
    strcpy(newNode->songName, songName);
    newNode->next = NULL;

    return newNode;
err:
    free(newNode->songName);
    free(newNode);
    return 0;
}


Node *insertNode(Node **head, Node *newNode) {
    if(!head || !newNode) return NULL;

    if(!*head) {
        *head = newNode;
    } else {
        Node *current;
        for(current = *head; current->next; current = current->next);
        current->next = newNode;
    }
    return *head;
}

void printNodes(Node *head) {
    for(Node *current = head; current; current = current->next) {
        printf("%s\n", current->songName);
    }
}

int main() {
    Node *head = NULL;
    insertNode(&head, createNode("hello"));
    insertNode(&head, createNode("world"));
    printNodes(head);
}

在我的链接列表中插入第三个节点时，我的代码似乎超时

While Inserting the 3rd node in my linked list my code seems to timeout

c

linked-list