Using a while loop to check the content of struct - c

Question

I'm trying to append a node to a linked list however, when I use a while loop to check if the "link" is set to NULL, the loop is being executed when it shouldn't.
It is as if the "cursor->link" was not set to NULL and the code inside the while loop is being executed, I put the print statement there just to test it and it is being executed even though "cursor->link" is set to NULL. The create function returns a "node*".
EDIT - I apologize guys, I posted this question late at night and I guess I might not have been in the best shape to express myself properly. Plus I'm still a bit confused about how to handle and work with Linked Listing (as my code probably shows). I've been given a template to work with (as in the functions append and display were preset and I've to work with them as is). The compiler did not set off any warnings with the code as is. However the program still crashes in the append function around the While loop.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef struct node {
int data;
struct node * link;
} node;
node* create(int data,node* link) {
node* newNode = (node*)malloc(sizeof(node));
newNode->data = data;
newNode->link = link;
return newNode;
}
void append ( node **, int ) ;
void display ( node * ) ;
int main() {
node *p ;
p=NULL;
int n;
char ch[10];
do {
printf("Enter the value\n");
scanf("%d",&n);
append(&p,n);
printf("Do you want to add another node? Type Yes/No\n");
scanf("%s",ch);
}while(!strcmp(ch,"Yes"));
printf("The elements in the linked list are");
display(p);
printf("\n");
return 0;
}
/* adds a node at the end of a linked list */
void append ( node **q, int num ){
node *cursor;
if (*q == NULL) {
*q = create(num, NULL);
node *cursor = *q;
}
while(cursor->link != NULL) {
printf("1\n");
cursor = cursor->link;
}
node* newNode = create(num, NULL);
cursor->link = newNode;
}
void display ( node *q ){
node *cursor = q;
while(cursor->link != NULL) {
printf(" %d", q->data);
cursor = cursor->link;
}
printf(" %d", cursor->data);
}

Answer 1

As Ry mentioned, problem is with the cursor you are using in while loop, it's never initialized. Instead you are creating a new variable with the same name when *q is null. I see one more problem in your code, when list is empty you are adding new node twice. First in null check condition and then after while loop.
To fix move this line
"node *cursor = *q"
outside if condition and add a return instead. Also remove this line
"node *cursor"
Note:: I am assuming your create method has no issue.