C编程编译问题

Question

嗨，我正准备面试，其中大部分编程都是用C语言完成的。我决定在C语言中实现一个链接列表类，以便了解如何以低级语言真正实现对象不支持面向对象的范例。我遇到了一些编译问题，所以熟悉C的人请帮忙（我从来没有用C编写过）。我在下面发布了我的代码以及之后的编译错误。

//Creating a LinkedList in C 
//with 3 basic operations 
#include <stdio.h> 
typedef struct node { 
    int data; 
    node* next; 
} List; 

void insertEnd(List *node, int elem); 
void PrintList(List *node); 
/*void insertEnd(List *node, int elem); 
void remove(List *node, int elem);*/ 

int main() { 
    List *head = (List *)malloc(sizeof(List)); 
    head->data = 0; 
    head->next = NULL; 
    insertEnd(head, 3); 
    insertEnd(head, 4); 
    PrintList(head); 
} 
void insertEnd(List *node, int elem) { 
    while (node->next != NULL) { 
     node = node->next; 
    } 
    List *new_node = (List *)malloc(sizeof(List)); 
    new_node->data = elem; 
    new_node->next = NULL; 
    node->next = new_node; 
} 

void PrintList(List *node) { 
while (node) { 
    printf ("%i ->", node->data); 
    node = node->next; 
} 
} 

的错误如下：

bash-4.1$ gcc -o LinkedList LinkedList.c 
LinkedList.c:6: error: expected specifier-qualifier-list before ‘node’ 
LinkedList.c: In function ‘main’: 
LinkedList.c:15: warning: incompatible implicit declaration of built-in function ‘malloc’ 
LinkedList.c:17: error: ‘List’ has no member named ‘next’ 
LinkedList.c: In function ‘insertEnd’: 
LinkedList.c:24: error: ‘List’ has no member named ‘next’ 
LinkedList.c:25: error: ‘List’ has no member named ‘next’ 
LinkedList.c:27: warning: incompatible implicit declaration of built-in function ‘malloc’ 
LinkedList.c:29: error: ‘List’ has no member named ‘next’ 
LinkedList.c:30: error: ‘List’ has no member named ‘next’ 
LinkedList.c: In function ‘PrintList’: 
LinkedList.c:36: error: ‘List’ has no member named ‘next’ 

Answer 1

成员next应该struct node *next和你声明必须包含stdlib.h其中包含声明malloc：

而且您必须编译-Wall标志，直到您的程序没有错误。

#include <stdlib.h> 

// ... 

typedef struct node { 
    int data; 
    struct node *next; 
} List; 

// ... 

Answer 2

变化

typedef struct node { 
    int data; 
    node* next; 
} List; 

到

typedef struct node { 
    int data; 
    struct node* next; 
} List;