Thread: Please help me with Linklist problem

I write a link list program of three functions 1. "ref.h" 2. "main.c" 3. "create.c"
"create.c" accepts parameters from main.c and add an new item to the link list
I use pointer to pass the parameters to create.c, but I found my "front" variable in "create.c" is always NULL even though I have assigned new to it in the first item to be added.
Could anyone help me to find why? I have stuck in this question for hours =.=
Thank you very much!!

ps. I run my program in Linux environment

In ref.h

Code:

#include <stdio.h>
struct data{
        int postcode;
        struct data *next;
};

In main.c

Code:

#include "ref.h"
void main()
{

        struct data *front=NULL;
        struct data *end=NULL;

        int a;
        while(1)
        {
                printf("Add item to link list:\n");
                printf("Enter 1 to add link list\n");
                scanf("%d",&a);
                switch(a)
                {
                        case 1:{                        
                                    create(front,end);
                                    break;
                                }               
                        default:
                                exit(0);
                }
        }
}

In create.c

Code:

#include "ref.h"

void create(struct data *front,struct data *end)
{
        struct data *new=(struct data *)malloc(sizeof(struct data));
        printf("Please enter the postcode:\n");
        int i;
        scanf("%d",&i);
        new->postcode=i;
        new->next=NULL;
        if(front==NULL)               each time the create function only runs in if 
        {
                front=new;
                end=new;
                printf("First create!\n");
        }
        else
        {
                end->next=new;
                end=new;
                printf("In create!\n");
        }

}