linked list

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


typedef struct node
{
    char *name;
    struct node* nxt;
    struct node* pre;
}Node;

typedef struct dqueue
{
    struct node* first;
    struct node* last;
    int amount;
}Dqueue;


Node *baslangic = NULL;
Dqueue *dq;

void add_to_front(char *ad)
{
    printf(">add_to_front%s\n",ad);
    Node *added = (Node*)malloc(sizeof(Node));
    added->name=ad;
    added->nxt=NULL;
    added->pre=dq->last;
    if (baslangic==NULL)
    {
        baslangic=added;
        dq->first=added;
        dq->last=added;
        added->pre=NULL;
        added->nxt=NULL;
        dq->amount=1;
    }
    else
    {
        dq->last->nxt=added;
        dq->last=added;
        dq->amount++;
    }

}

void add_to_back(char *ad)
{
    printf(">add_to_back%s\n",ad);
    Node *added = (Node*)malloc(sizeof(Node));
    added->name=ad;
    added->pre=NULL;
    added->nxt=dq->first;
    if (baslangic==NULL)
    {
        baslangic=added;
        dq->first=added;
        dq->last=added;
        added->pre=NULL;
        added->nxt=NULL;
        dq->amount=1;
    }
    else
    {
        dq->first->pre=added;
        dq->first=added;
        dq->amount++;
    }

}


void print()
{
    printf(">print\n");
    if (dq->amount==0)
    {
        return;
    }
    Node *tmp;
    tmp=dq->last;
    while (tmp!=dq->first)
    {
        printf("%s\n",tmp->name);
        tmp=tmp->pre;
    }
    printf("%s\n",tmp->name);
}

void d_free()
{

}

void check_front()
{
    printf(">check_front\n");
    if (dq->amount==0)
    {
        return;
    }

    printf("%s\n",dq->last->name);
}

void check_back()
{
    printf(">check_front\n");
    if (dq->amount==0)
    {
        return;
    }

    printf("%s\n",dq->first->name);
}

void remove_from_front()
{
    printf(">remove_from_front\n");
    if (dq->amount==1)
    {
        dq->first=NULL;
        dq->last=NULL;
        dq->amount=0;
        return;
    }
    if (dq->amount==0)
    {
        return;
    }
    dq->last->pre->nxt=NULL;
    dq->last=dq->last->pre;
    dq->amount--;
}


void remove_from_back()
{
    printf(">remove_from_back\n");
    if (dq->amount==1)
    {
        dq->first=NULL;
        dq->last=NULL;
        dq->amount=0;
        return;
    }
    if (dq->amount==0)
    {
        return;
    }
    dq->first->nxt->pre=NULL;
    dq->first=dq->first->nxt;
    dq->amount--;
}

int main()
{
    dq = malloc(sizeof(Dqueue));
    dq->amount=0;
    char command[50];
    char parameter[1000];
    while (scanf("%s",command)!=EOF)
    {
        if (strcmp(command,"add_to_front")==0)
        {
            gets(parameter);
            add_to_front(parameter);
        }
        else if (strcmp(command,"add_to_back")==0)
        {
            gets(parameter);
            add_to_back(parameter);
        }
        else if (strcmp(command,"remove_from_back")==0)
            remove_from_back(parameter);
        else if (strcmp(command,"remove_from_front")==0)
            remove_from_front();
        else if (strcmp(command,"check_front")==0)
            check_front();
        else if (strcmp(command,"check_back")==0)
            check_back();
        else if (strcmp(command,"print")==0)
            print();
        else
        {
            printf(">%s\n",command);
            printf(" HUH?\n");
        }
    }

    return 0;
}