C中的链表实现

Question

In the following code for a linked list implementation, I am getting the error cannot convert node_type to node * for argument 1 to 'node *insert(node *)' . I don't understand this message. Basically the program is not able to call the function insert from main() .

Can anyone help explain this?

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

struct node_type
{
    int data;
    node_type *next;
};

typedef struct node_type node;

node  *insert(node *head);
void print1(node *temp);

int main(void){
    int dat;
    char x,ch;

    node *temp;


    temp=NULL;
    printf("do u wanna enter a new node? \n");
    scanf("%c", &x);
    if (x=='y' or x=='Y'){

        temp=(node *)malloc(sizeof(node));
        printf("enter the data: \n");
        scanf("%d ", &dat);

        temp->data= dat;
        temp->next = NULL;
    }

    printf("do u want to insert another element?\n");
    scanf("%c ", &ch);
    if( ch=='y' or ch=='Y'){
        insert(temp);
    }
    print1(temp);

    getch();

}
node *insert(node *temp)
{
    int dat;
    char ch1;
    node *newnode;

    newnode=(node *)malloc(sizeof(node));

    printf("enter the data: ");
    scanf("%d", &dat);
    newnode->data=dat;
    newnode->next=temp;
    temp=newnode;

    printf("do u want to insert another element?\n");
    scanf("%c ", &ch1);
    if( ch1=='y' or ch1=='Y'){
        insert(temp);
    }
    else return temp;

}
void print1(node *temp)
{
    int t;

    while(temp!= NULL){
        t= temp->data;
        temp= temp->next;
        printf(" %d ", t);
    }
}

Answer 1

A few problems in your code:

1. The definition of struct node_type

    struct node_type { int data; node_type *next; }; 

   is not right according to C syntax, type node_type does not exist before the typedef struct node_type node; statement.

   To fix this, you could

   a) define struct node_type like this

    struct node_type { int data; struct node_type *next; }; 

   or

   b) use (Thanks @yongzhy)

    typedef struct node_type { int data; struct node_type *next; }; 

   or

   c) compile your code with a C++ compiler. (Thanks @JonathanLeffler)

2. All these

    if (x=='y' or x=='Y'){ 

   should be replaced by

    if (x=='y' || x=='Y'){ 

   or you could just include <iso646.h> , which includes #define or || in it (Thanks @JonathanLeffler),

   or you should compile your code with a C++ compiler.

Answer 2

add to @leeduhem

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

this will void additional line of

typedef struct node_type node;