单链表的插入与删除

#include

#include

typedef struct LNode{
    int data;
    struct LNode *next;
}LNode, *LinkList;

LinkList List_Init(){
    LinkList p = (LinkList)malloc(sizeof(LNode));
    p->next = NULL;
    return p;
}

LinkList Get_Elem_i(LinkList L,int i){//按给定位置查找链表中数据
	//带有头结点的单链表
    LinkList p = L->next;//首结点
    int j = 1;//统计个数
    if(i<0)
        return NULL;
    if(i==0)
        return L;//返回头结点
    while(p && jnext;
        j++;
    }
    return p;
}

LinkList Get_Elem_e(LinkList L,int e){//按给定值查找是否有此元素，有则返回，无则返回NULL
	//带有头结点的单链表
    LinkList p = L->next;
    while(p && p->data!=e){
        p = p->next;  //找不到就继续查找
    }
    return p;//找到就返回
}

LinkList List_HeadInsert(LinkList L){
    int x;
    LinkList s;
	
    scanf("%d",&x);
    while(x!=9999){
        s = (LinkList)malloc(sizeof(LNode));
        s->data = x;
        s->next = L->next;
        L->next = s;
        scanf("%d",&x);
    }
    return L;
}

LinkList List_TailInsert(LinkList L){
    int x;
    LinkList r = L;
    LinkList s;
	
    scanf("%d",&x);
    while(x!=9999){
        s = (LinkList)malloc(sizeof(LNode));
        s->data = x;
        r->next = s;
        r = s;
        scanf("%d",&x);  
    }
    r->next = NULL;
    return L;
	
}

void ListTraverse(LinkList L){
	
	LinkList p = L->next;
	while(p){
		printf("%d ",p->data);
		p = p->next;
	}
	printf("\n");
}


LinkList Insert_Elem(LinkList L,int i,int num){//在i位置插入结点
    LinkList p = Get_Elem_i(L,i-1);//找到要插入位置的前驱结点
	
	LinkList s = (LinkList)malloc(sizeof(LNode));
	s->data = num;
	s->next = p->next;
	p->next = s;
	
	return L;
	
}

LinkList Delete_Elem(LinkList L,int i){//删除第i个结点
	
	LinkList p = Get_Elem_i(L,i-1);//找到要删除的结点的前驱结点
	LinkList q = p->next;
	p->next = q->next;
	free(q);

	return L;
}

int main(){
	LinkList L = List_Init();
	
    int x = 1;
	int y = 0;
	int num = 0;
	scanf("%d%d",&x,&num);
	while(x!=9999 && num!=9999){
		Insert_Elem(L,x,num);
		scanf("%d%d",&x,&num);
	} 
	ListTraverse(L);



	scanf("%d",&y);
	Delete_Elem(L,y);
    ListTraverse(L);
    return 0;
}