Displaying and Deleting Elements in a Linked List

This is a discussion on Displaying and Deleting Elements in a Linked List within the C Programming forums, part of the General Programming Boards category; I'm having problems displaying the elements in this linked list. Whenever the program runs, it just displays the last element ...

  1. #1
    Registered User
    Join Date
    Dec 2011
    Posts
    1

    Displaying and Deleting Elements in a Linked List

    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!

    Code:
    #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);
        }
    }

  2. #2
    Registered User
    Join Date
    Sep 2006
    Posts
    8,868
    Welcome to the forum, Camille!

    Impressive post, as well.

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