Double Linked List

Penggunaan Fungsi Push depan, push belakang, pop depan, pop belakang

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

struct data
{
    int angka;
    struct data *next, *prev;
}*head = NULL, *tail = NULL, *curr = NULL;

void clear()
{
    for(int c=0; c<25; c++)
        printf("\n");
}

void push_depan(int angka)
{
    curr = (struct data*)malloc(sizeof(struct data));
    curr->angka = angka;
    curr->next = curr->prev = NULL;

    if(head==NULL)
    {
        head = tail = curr;
    }
    else
    {
        head->prev = curr;
        curr->next = head;
        head = curr;
    }
}

void push_belakang(int angka)
{
    curr = (struct data*)malloc(sizeof(struct data));
    curr->angka = angka;
    curr->next = curr->prev = NULL;

    if(head==NULL)
    {
        head = tail = curr;
    }
    else
    {
        tail->next = curr;
        curr->prev = tail;
        tail = curr;
    }
}

void cetak()
{
    if(head==NULL)
    {
        printf("data kosong");
    }
    else
    {
        curr = head;
        while(curr)
        {
            printf("%d ", curr->angka);
            curr=curr->next;
        }
    }
}

void pop_depan()
{
    if(head==NULL)
    {
        printf("tidak ada data");
        getchar();
    }
    else if(head==tail)
    {
        curr=head;
        free(curr);
        head = tail = curr = NULL;
    }
    else
    {
        curr=head;
        head=head->next;
        free(curr);
        head->prev = NULL;
    }
}

void pop_belakang()
{
    if(head==NULL)
    {
        printf("tidak ada data");
        getchar();
    }
    else if(head==tail)
    {
        curr=head;
        free(curr);
        head = tail = curr = NULL;
    }
    else
    {
        curr=tail;
        tail=tail->prev;
        free(curr);
        tail->next = NULL;
    }
}

void main()
{
    int angka, pilih, pilih2, pilih3;

    do
    {
        clear();
        printf("1. Input\n");
        printf("2. View\n");
        printf("3. Delete\n");
        printf("4. Exit\n");
        printf("Pilih : ");
        scanf("%d", &pilih); fflush(stdin);

        switch(pilih)
        {
        case 1 :
            {
                clear();
                do
                {
                    printf("1. Push Depan\n");
                    printf("2. Push Belakang\n");
                    printf("Pilih : ");
                    scanf("%d", &pilih2); fflush(stdin);
                }while(pilih2!=1 && pilih2!=2);

                if(pilih2==1)
                {
                    printf("Masukan Angka : ");
                    scanf("%d", &angka); fflush(stdin);
                    push_depan(angka);
                }
                else if(pilih2==2)
                {
                    printf("Masukan Angka : ");
                    scanf("%d", &angka); fflush(stdin);
                    push_belakang(angka);
                }
                break;
            }
        case 2 :
            {
                clear();
                cetak();
                getchar();
                break;
            }
        case 3 :
            {
                clear();
                do
                {
                    printf("1. Pop Depan\n");
                    printf("2. Pop Belakang\n");
                    printf("Pilih : ");
                    scanf("%d", &pilih3); fflush(stdin);
                }while(pilih3!=1 && pilih3!=2);

                if(pilih3==1)
                {
                    pop_depan();
                }
                else if(pilih3==2)
                {
                    pop_belakang();
                }
                break;
            }
        }
    }while(pilih!=4);
}