list_link_sv

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

typedef struct sinhvien
{
    char ht[50], qq[50];
    float diem;
}
typedef struct Node
{
    item Data;
    Node *next;
};

typedef Node *List;

void Init (List &L)
{
    L=NULL;
}

int Isempty (List L)
{
    return (L==NULL);
}

int Len (List L)
{
    Node *P=L;
    int i=0;
    while (P!=NULL)
    {
        i++;
        P=P->next;
    }
    return i;
}

void Make_sv (item &sv)
{
    char ht[50], qq[50];
    float diem;

    printf ("\tHo ten: ");
    fflush(stdin);
    gets(ht);
    strcpy(sv.ht,ht);

    printf ("\tQue quan: ");
    fflush(stdin);
    gets(qq);
    strcpy(sv.qq,qq);

    fflush(stdin);
    printf ("\tDiem: ");
    scanf("%f",&diem);
    sv.diem=diem;
}

void Make_Node (Node *P, item sv)
{
    P->next = NULL;
    strcpy (P->Data.ht,sv.ht);
    strcpy (P->Data.qq,sv.qq);
    P->Data.diem = sv.diem;
}

void Insert_first (List &L, item sv)
{
    Node *P;
    P = (Node *) malloc (sizeof (Node));
    Make_Node(P,sv);
    P->next = L;
    L = P;
}

void Insert_k (List &L, item sv, int k)
{
    Node *P, *Q = L;
    P = (Node *) malloc (sizeof (Node));
    int i=1;
    if (k<1 || k> Len(L)+1) printf("Vi tri chen khong hop le !");
    else
    {
        Make_Node(P,sv);
        if (k == 1) Insert_first(L,sv);
        else
        {
            while (Q != NULL && i != k-1)
            {
                i++;
                Q = Q->next;
            }
            P->next = Q->next;
            Q->next = P;
        }
    }
}

int Search_ht (List L, char ht[50])
{
    Node *P=L;
    int i=1;
    while (P != NULL && strcmp(P->Data.ht,ht))
    {
        P = P->next;
        i++;
    }
    if (P != NULL) return i;
    else return 0;
}

int Search_qq (List L, char qq[50])
{
    Node *P=L;
    int i=1;
    while (P != NULL && strcmp(P->Data.qq,qq))
    {
        P = P->next;
        i++;
    }
    if (P != NULL) return i;
    else return 0;
}

void Del_frist (List &L, item &sv)
{
    sv = L->Data;
    L = L->next;
}

void Del_k (List &L, item &sv, int k)
{
    Node *P=L;
    int i=1;
    if (k<1 || k>Len(L)) printf("Vi tri xoa khong hop le !");
    else
    {
        if (k==1) Del_frist(L,sv);
        else
        {
            while (P != NULL && i != k-1)
            {
                P=P->next;
                i++;
            }
            P->next = P->next->next;
        }
    }
}

void Del_sv_ht (List &L, item &sv, char ht[50])
{
    while (Search_ht(L,ht)) Del_k (L,sv,Search_ht(L,ht));
}

void Input (List &L)
{
    int i=0;
    char ht[50], qq[50];
    float diem;
    item sv;
    do
    {
        i++;
        printf ("Nhap thong tin sinh vien thu %d : \n",i);
        printf ("\tHo ten: ");
        fflush(stdin);
        gets(ht);
        if (ht[0] !='\0')
        {
            strcpy(sv.ht,ht);
            printf ("\tQue quan: ");
            fflush(stdin);
            gets(qq);
            strcpy(sv.qq,qq);
            fflush(stdin);
            printf ("\tDiem: ");
            scanf("%f",&diem);
            sv.diem=diem;
            Insert_k(L,sv,Len(L)+1);
        }

    } while(ht[0] !='\0');
}

void Output (List L)
{
    Node *P=L;
    printf ("%20s %20s %10s\n","Ho ten","Que quan","Diem");
    while (P != NULL)
    {
        printf("%20s %20s %10.2f\n",P->Data.ht,P->Data.qq,P->Data.diem);
        P = P->next;
    }
    printf("\n");
}

int main()
{
    List L;
    Init(L);
    Input(L);
    Output(L);

    int lua_chon;
    printf("Moi ban chon phep toan voi DS LKD:");
    printf("\n1: Kiem tra DS rong");
    printf("\n2: Do dai DS");
    printf("\n3: Chen sinh vien vao vi tri k trong DS");
    printf("\n4: Tim sinh vien theo Ho ten");
    printf("\n5: Tim sinh vien theo Que quan");
    printf("\n6: Xoa sinh vien tai vi tri k");
    printf("\n7: Xoa sinh vien theo Ho ten");
    printf("\n8: Thoat");
    do
    {
        printf("\nBan chon: ");
        scanf("%d",&lua_chon);
    switch (lua_chon)
    {
        case 1:
        {
            if (Isempty(L)) printf("DS rong !");
            else printf ("DS khong rong !");
            break;
        }
        case 2: printf ("Do dai DS la: %d.",Len(L));break;
        case 3:
        {
            item sv;
            int k;
            printf ("Nhap phan tu can chen vao DS: \n");
            Make_sv(sv);
            printf ("Nhap vi tri can chen: ");
            scanf ("%d",&k);
            Insert_k (L,sv,k);
            printf ("DS sau khi chen:\n");
            Output(L);
            break;
        }
        case 4:
        {
            char ht[50];
            printf ("Moi ban nhap vao Ho ten can tim: ");
            fflush(stdin);
            gets(ht);
            int k = Search_ht (L,ht);
            if (k) printf ("Tim thay sinh vien co %s trong DS tai vi tri thu: %d",ht,k);
            else printf ("Khong tim thay sinh vien co %d trong danh sach !",ht);
            break;
        }
        case 5:
        {
            char qq[50];
            printf ("Moi ban nhap vao Que quan can tim: ");
            fflush(stdin);
            gets(qq);
            int k = Search_qq (L,qq);
            if (k) printf ("Tim thay sinh vien co %s trong DS tai vi tri thu: %d",qq,k);
            else printf ("Khong tim thay sinh vien co %d trong danh sach !",qq);
            break;
        }
        case 6:
        {
            int k;
            item sv;
            printf ("Nhap vi tri can xoa: ");
            scanf ("%d",&k);
            Del_k (L,sv,k);
            printf ("DS sau khi xoa:\n");
            Output(L);
            break;
        }
        case 7:
        {
            item sv;
            char ht[50];
            printf ("Nhap Ho ten can xoa: ");
            fflush(stdin);
            gets(ht);
            Del_sv_ht (L,sv,ht);
            printf ("DS sau khi xoa:\n");
            Output(L);
            break;
        }
        case 8: break;
    }
    }while (lua_chon !=7);
    return 0;
}