c - 编译简单链表程序时出现未声明节点错误

Question

代码

#include <stdio.h>

void main()
{
     struct Node      //defining a node
     {
          int data;             //defining the data member
          struct Node *next;    //defining a pointer to Node type variable
     };

      struct Node *head;        //declaring a pointer variable 'head' to a Node type variable.   
      head=NULL;                //Since the head pointer now points nothing,so initialised with NULL.

      struct Node* temp = (Node*)malloc(sizeof(struct Node));//creating a node and storing its adrs in pointer 'temp'
     (*temp).data=2;          //node's data part is initialised.
     (*temp).next= NULL;    //the node points to nothing initially
     head=temp;             //head is initialised with address of the node,so now it points to the node 

     printf("%d",temp->data);
 }

Answer 1

你应该写

struct Node* temp = (struct Node*)malloc(sizeof(struct Node));

而不是

 struct Node* temp = (Node*)malloc(sizeof(struct Node));

因为结构标记与通常的标识符位于不同的命名空间中。因此需要使用 struct 关键字来指定这一点。阅读 this

此外还包括<stdlib.h>否则您将收到一条警告，表明您正在隐式声明 malloc。