linkedlist_FamiHug

//by FamiHug@FAMILUG
#include <stdio.h>
#include <stdlib.h>

int init();
void insert_head(int);
void insert_tail(int);
void delete_head();
void delete_tail();

typedef struct pointer
{
        int info;
        struct pointer *link;
}dslk;

dslk *l,*p;
int n,d,i;
float s;

int main()
{
        int x;
        int init();
        printf("CHUONG TRINH MINH HOA DANH SACH LIEN KET DON\n");
        printf("Ung dung de tinh trung binh cong cua cac phan tu chan trong day so nhap vao\n");
        printf("======================================================\n");
        printf("Nhap vao so phan tu cua danh sach: ");
        scanf("%d",&n);
        if(n>=0)
{
        for(i=1;i<=n;i++)
        {
        printf("Phan tu thu %d:",i);
        scanf("%d",&x);
        insert_head(x);
        }

        s=0;
        d=0;
        p=l;
        for(i=1;i<=n;i++)
        {
                if(p->info %2 ==0)
                {
                        d++;
                        s=s+p->info;
                }
                p=p->link;
        }
        if(d!=0) printf("TBC=%f",s/d);
        else printf(" Khong co phan tu nao chia het cho 2 ");
}else printf("So nhap vao khong hop le. Chuong trinh ket thuc");

 return 0;
}


int init()
{
        l=NULL;
        return 0;
}
void insert_head(int x)
{
        p=(dslk *)malloc(sizeof(dslk));
        p->info=x;
        p->link=l;
        l=p;
}
void insert_tail(int x)
{
        dslk *q;
        q=(dslk *)malloc(sizeof(dslk));
        p->info=x;
        p->link=NULL;
        if(l==NULL) l=p;
        else
        {
                q=l;
                while(q->link!=NULL)
                {
                        q=q->link;
                }
                q->link=p;
        }
}
void delete_head()
{
        if(l==NULL) printf("\n Danh sach rong");
        else
        {
                p=l;
                l=l->link;
                free(p);
        }
}
void delete_tail()
{
        dslk *q;
        if(l==NULL) printf("\n Danh sach rong");
        else
        {
                if (l==NULL)
                        {
                                p=l;
                                l=NULL;
                                free(p);
                         }
                 else
                        {
                                q=l;
                                while (q->link->link !=NULL)
                                {
                                        q=q->link;
                                        p=q->link;
                                        q->link=NULL;
                                        free(p);
                                }
                        }
                }
}