王道c语言ch11-单链表的新建、插入、删除例题

cpp 复制代码
#include <stdio.h>
#include <stdlib.h>
#define END 33

typedef int ElemType;

typedef struct LNote {
    ElemType data;
    struct LNote *next;
} LNote, *LinkList;

//头插法
void list_head_insert(LinkList &L) {
    ElemType x;
    L = (LinkList) malloc(sizeof(LNote));
    L->next = NULL;
    scanf("%d", &x);
    while (x != END) {
        LinkList s = (LinkList) malloc(sizeof(LNote));
        s->data = x;
        s->next = L->next;
        L->next = s;
        scanf("%d", &x);
    }
}

//尾插法
void list_tail_insert(LinkList &L) {
    ElemType x;
    L = (LinkList) malloc(sizeof(LNote));
    L->next = NULL;
    scanf("%d", &x);
    LinkList s,r=L;
    while (x != END) {
        s = (LinkList) malloc(sizeof(LNote));
        s->data = x;
        r->next = s;
        r=s;
        scanf("%d", &x);
    }
    r->next=NULL;
}

//打印单链表中所有结点的值
void list_print(LinkList P){
    P=P->next;
    printf("LinkList is :");
    while (P!=NULL){
        printf("%d   ",P->data);
        P=P->next;
    }
    printf("\n");
}

//按位查找，返回结点
LinkList GetElem(LinkList L,int post){
    int i=0;
    if (post<0){ //post<0返回NULL post=0返回头指针
        return NULL;
    }
    while (L&&i<post){
        L=L->next;
        i++;
    }
    return L;
}

//按值查找，返回结点
LinkList LocateElem(LinkList L,ElemType data){
    while (L){
        L=L->next;
        if(L->data == data){
            return L;
        }
    }
    return NULL;
}

//往post的位置插入结点
bool InsertElem(LinkList L,int post,ElemType InsertData){
    LinkList ret = GetElem(L,post-1);
    if (ret){
        LinkList s=(LinkList) malloc(sizeof (LNote));
        s->data=InsertData;
        s->next=ret->next;
        ret->next=s;
        return true;
    } else{
        return false;
    }
}

//删除结点
bool ListDelete(LinkList L,int i){  //不改变头结点，则不用加引用
    LinkList p= GetElem(L,i-1); //i=1,返回头指针
    //当i<=0,p=NUll，则LinkList q=p->next;会报错
    if(NULL==p){
        return false;
    }
    LinkList q=p->next;  //不直接q->next=q->next->next;是为了释放删掉的结点内存
    p->next=q->next;
    free(q);
    return true;
};

int main() {
    LinkList L;
    list_tail_insert(L);

    bool ret = InsertElem(L,2,66);{
        if (ret){
            printf("insert is ture");
        } else{
            printf("insert is fault");
        }
    }
    list_print(L);
    LinkList search = GetElem(L,2);
    if(search){
        printf("function of GetElem return %d\n",search->data);
    } else{
        printf("function of GetElem return null\n");
    }
    LinkList getdata = LocateElem(L,2);
    if(getdata){
        printf("function of LocateElem return %d\n",getdata->data);
    } else{
        printf("function of LocateElem return null\n");
    }

    ListDelete(L,4);list_print(L);
    return 0;
}
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