Typedef's and nodes - c

Question

This code is supposed to build a simple linked list containing integers from 0 to 20. I keep getting the error: unknown type name 'node' when I compile my code for what seems every instance of node in the program. I'm not sure if I have to define them or there is a bigger flaw in the code.
#include<stdio.h>
#include<stdlib.h>
int main() {
int i;
struct node *first=NULL;
for(i=1;i<=20;i++)
first=insertrear(first,i);
dispnodes(first);
sum(first);
return 0;
}
typedef struct node {
int data;
struct node *link;
};
node* getnode(node *temp,int i) {
temp=(node*)malloc(sizeof(node));
temp->data=i;
temp->link=NULL;
return temp;
}
node* insertrear(node *first,int a) {
node *temp=NULL,*i;
temp= getnode(temp,a);
if(first==NULL) {
first=temp;
return first;
}
for(i=first;i->link!=NULL;i=i->link);
i->link=temp;
return first;
}
void dispnodes(node *first) {
int j;
if(first==NULL) {
printf("\nlist empty");
return;
}
node *i;
for(i=first,j=0;i!=NULL;j++,i=i->link)
printf("\nNode #%d contains %d ",j,i->data);
}
void sum(node *first) {
node *i;
int total=0;
for(i=first;i!=NULL;i=i->link)
total+=i->data;
printf("\nThe sum total of all nodes in this list is %d",total);
}

Answer 1

You either need to specify a label for the typedef struct node or not typedef the struct node.
The way you are using it, you can do following.
/* Forward declare typedef _node to node */
typedef struct node_ node;
/* Define struct node_ */
struct node_ {
int data;
node *link;
};
You should have the forward declaration above your main(), so that you can use it there as well.

Answer 2

typedef struct node {
int data;
struct node *link;
}node;
int main() {
int i;
struct node *first=NULL;
for(i=1;i<=20;i++)
first=insertrear(first,i);
dispnodes(first);
sum(first);
return 0;
}

Answer 3

There are two things you have to modify:
you have to declare the the struct ,typedef and all the functions you are calling before main function.Compiler should be provided with the declaration before it encounters any of them.
Also you haven't provided a label to the typedef to structure node,you can do something like this:
typedef struct node {
int data;
struct node *link;
} Node ;
or use struct node instead of node to declare a variable of struct node type
Here is the code after modification:
typedef struct node
{
int data;
struct node *link;
} Node ;
void dispnodes(Node *first);
node* insertrear(Node *first,int a);
void sum(Node *first);
int main() {
int i;
struct node *first=NULL;
for(i=1;i<=20;i++)
first=insertrear(first,i);
dispnodes(first);
sum(first);
return 0;
}
// rest of the code