C list->data doesnt show on terminal - c

Question

The console doesnt show the data from my list node.I filled it with chars that i took from a text File.
#include<stdio.h>
#include<stdlib.h>
struct list_node{
char data;
struct list_node* next;
};
typedef struct list_node* node;
node insert_right(node list,char data)
{
node new_node = (node) malloc(sizeof(struct list_node));
new_node->data = data;
new_node->next = list->next;
list->next = new_node;
return new_node;
}
int main()
{
FILE *fr = fopen("dat1.txt","r");
node list = (node) malloc(sizeof(struct list_node));
int i;
while((i = fgetc(fr)) != EOF){
insert_right(list,i);
}
printf("%c",list->data);
}
The main problem i think would be in the insert method.

Answer 1

You are creating a linked list. Each node you create needs to point to either NULL or the next node. You were not quite making the links. Also you were not getting the new_node you you were returning. Also when printing out a list you have to go through each node (like an array).
#include<stdio.h>
#include<stdlib.h>
struct list_node{
char data;
struct list_node* next;
};
typedef struct list_node* node;
node insert_right(node list,char data)
{
node new_node = (node) malloc(sizeof(struct list_node));
new_node->data = data;
list->next = new_node;
new_node->next = NULL;
return new_node;
}
int main()
{
FILE *fr = fopen("dat1.txt","r");
node list = (node) malloc(sizeof(struct list_node));
int i;
node next = list;
while((i = fgetc(fr)) != EOF){
next = insert_right(next,i);
}
node print = list;
while(print != NULL){
printf("%c",print->data);
print = print->next;
}
}

Answer 2

You are allocating memory to a node called list, but yet you do not initialize any value for data, it can be garbage or any character that does not show up in the console.
When you insert a new value, a new node is created and the first one, the "head" so to speak, is still uninitialized even though it is pointing to a second node that has a meaningful data there.
This is your list:
// Node Y (X) indicates the Y-th node that has a X value.
Node1 (garbage) -> Node2 (value) -> Node3 (value) -> garbage
The last node of your list (which is also the first when you create it) should be pointing to NULL instead of being uninitialized.
I am also pretty sure that your list is poor-implemented because the new elements are always being pointed by list, so you lose track of the ones you created before.
Here is a better version, in my opinion:
#include<stdio.h>
#include<stdlib.h>
struct list_node{
char data;
struct list_node* next;
};
typedef struct list_node* node;
void insert_right(node list,char data)
{
node new_node = (node) malloc(sizeof(struct list_node));
node temp = list;
// It runs through the list until it reaches the last node
while(temp->next != NULL) temp = temp->next;
temp->data = data;
temp->next = new_node;
new_node->next = NULL;
}
int main()
{
FILE *fr = fopen("dat1.txt","r");
// List points to only the first element of the list.
node list = (node) malloc(sizeof(struct list_node));
list->next = NULL;
int i;
while((i = fgetc(fr)) != EOF){
insert_right(list,i);
}
while(list != NULL) {
printf("%c",list->data);
list = list->next;
}
}

Answer 3

#include <stdio.h>
#include <stdlib.h>
struct list_node {
char data;
struct list_node* next;
};
int main()
{
FILE *fr = fopen("dat1.txt","r");
struct list_node *list = malloc(sizeof(*list)), *pos = list;
int i;
while ((i = fgetc(fr)) != EOF) {
pos->data = i;
pos->next = malloc(sizeof(*list->next));
pos = pos->next;
}
pos->next = NULL;
while (list->next) {
printf("%c ", list->data);
free(list); /* important!!!! */
list = list->next;
}
putchar('\n');
return 0;
}