Displaying and Deleting Elements in a Linked List

[Camille]

I'm having problems displaying the elements in this linked list. Whenever the program runs, it just displays the last element that was entered and not all. The program also stops if I try to delete an element. Please help me, guys. Thank you!

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


void display_menu();
int get_choice();
void add_new();
void delete_element();
void display_all();
void insert_beginning();
void insert_middle();
void insert_end();
void delete_beginning();
void delete_middle();
void delete_end();


typedef struct list {
    int data;
    struct list *next;
} lists;


lists *head, *tail;


main() {
    int choice;
    do{
        display_menu();
        choice=get_choice();
        switch (choice) {
            case 1: add_new(); break;
            case 2: delete_element(); break;
            case 3: display_all(); break;
            case 4: break;
        }
    } while (choice!=4);
}


void display_menu() {
    printf ("MENU\n");
    printf ("[1] Add new\n");
    printf ("[2] Delete element\n");
    printf ("[3] Display all\n");
}


int get_choice() {
    int choice;
    printf("\nYour choice: ");
    scanf ("%d", &choice);
    return choice;
}




void add_new() {
    int number;
    lists *node;
    head=NULL;
    tail=NULL;
    node=(lists *)malloc(sizeof(lists));
    printf ("Input an integer: ");
    scanf ("%d", &(node->data));
    if (head==NULL) {
        head=node;
        tail=node;
        tail->next=NULL;
    } else {
        if (node->data <= head->data)
            insert_beginning();
        else
            if (node->data >= tail->data)
                insert_end();
            else
                insert_middle();
    }
}


void insert_beginning() {
    lists *node;
    node->next=head;
    head=node;
}


void insert_middle() {
    lists *temp, *node;
    while (temp->next->data <= node->data)
        temp=temp->next;
}


void insert_end() {
    lists *node;
    tail->next=node;
    tail=node;
    tail->next=NULL;
}


void delete_element() {
    int num;
    lists *node;
    printf ("\nData to be deleted? ");
    scanf ("%d", &num);
    if (head->data==num)
        delete_beginning();
    else {
        if (tail->data==num)
            delete_end();
        else
            delete_middle();
    }
    display_menu();
}


void delete_beginning() {
    lists *temp;
    temp=head;
    head=head->next;
    free(temp);
    display_menu();
}


void delete_middle() {
    int num;
    lists *temp;
    head->next=temp;
    while (temp!=NULL){
        if (temp->data==num)
            free(temp);
    }
    display_menu();
}


void delete_end() {
    lists *temp;
    tail=temp;
    temp->next=NULL;
    tail=temp->next;
    free (temp);
    display_menu();
}


void display_all() {
    lists *temp;
    if (head==NULL)
        printf ("No elements to print!\n");
    else {
        temp=head;
        do {
            printf ("%d\n", temp->data);
            temp=temp->next;
        } while (temp!=NULL);
    }
}

[Adak]

Welcome to the forum, Camille!

Impressive post, as well.