Linked list c program

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

struct NODE {

    int number;
    struct NODE *next;

};

int search_value(struct NODE *llist, int num);

void append_node(struct NODE *llist, int num);

void display_list(struct NODE *llist);

void delete_node(struct NODE *llist, int num);

int main()
{

    int num = 0;
    int input = 1;
    int retval = 0;
    struct NODE *llist;

    llist = (struct NODE *) malloc(sizeof(struct NODE));
    llist->number = 0;
    llist->next = NULL;

    while (input != 0)
    {

        printf("\n-- Menu Selection --\n");
        printf("0) Quit\n");
        printf("1) Insert\n");
        printf("2) Delete\n");
        printf("3) Search\n");
        printf("4) Display\n");
        scanf("%d", &input);

        switch (input)
        {

            case 0:
            default:
                printf("Goodbye ...\n");
                input = 0;
                break;

            case 1:
                printf("Your choice: `Insertion'\n");
                printf("Enter the value which should be inserted: ");
                scanf("%d", &num);
                append_node(llist, num);
                break;

            case 2:
                printf("Your choice: `Deletion'\n");
                printf("Enter the value which should be deleted: ");
                scanf("%d", &num);
                delete_node(llist, num);
                break;

            case 3:
                printf("Your choice: `Search'\n");
                printf("Enter the value you want to find: ");
                scanf("%d", &num);
                if ((retval = search_value(llist, num)) == -1)
                    printf("Value `%d' not found\n", num);
                else
                    printf("Value `%d' located at position `%d'\n", num, retval);
                break;

            case 4:
                printf("You choice: `Display'\n");
                display_list(llist);
                break;

        } /* switch */
    } /* while */

    free(llist);
    return (0);
}

void display_list(struct NODE *llist)
{
    while (llist->next != NULL)
    {
        printf("%d ", llist->number);
        llist = llist->next;
    }

    printf("%d", llist->number);
}

void append_node(struct NODE *llist, int num)
{
    while (llist->next != NULL)
        llist = llist->next;

    llist->next = (struct NODE *) malloc(sizeof(struct NODE));
    llist->next->number = num;
    llist->next->next = NULL;
}

void delete_node(struct NODE *llist, int num)
{
    struct NODE *temp;
    temp = (struct NODE *) malloc(sizeof(struct NODE));

    if (llist->number == num)
    {
        /* remove the node */
        temp = llist->next;
        free(llist);
        llist = temp;
    } else
    {
        while (llist->next->number != num)
            llist = llist->next;

        temp = llist->next->next;
        free(llist->next);
        llist->next = temp;
    }
}

int search_value(struct NODE *llist, int num)
{
    int retval = -1;
    int i = 1;

    while (llist->next != NULL)
    {
        if (llist->next->number == num)
            return i;
        else
            i++;

        llist = llist->next;
    }

    return retval;
}

Output : 

-- Menu Selection --
0) Quit
1) Insert
2) Delete
3) Search
4) Display

Enter your option : 1
Your choice: `Insertion'
Enter the value which should be inserted: 34

Enter your option : 4
You choice: `Display'
0 34
Enter your option : 1
Your choice: `Insertion'
Enter the value which should be inserted: 60

Enter your option : 3
Your choice: `Search'
Enter the value you want to find: 60
Value `60' located at position `2'

Enter your option : 0
Goodbye ...