题解 | #牛牛的链表添加节点#

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

typedef struct list{
    int data;
    struct list *next;
}list,*linklist;

//链表内容打印
void ptink(list *head)
{
        struct list *point=head;

        while(point!=NULL)
        {
                printf("%d ",point->data);
                point=point->next;//while里面的判断其实是在判断point->next是否为NULL
        }
        putchar('\n');
}

#if 1
list *addList(list *head,int x,int n)
{
    int i=0;
    list *newlist = (list *)malloc(sizeof(list));
    newlist->data = x;
    newlist->next = NULL;
    
    list *point = head;
    for(i=1;;i++)
    {
        if(x==0)  //判断是否在链表头添加 
        {
            newlist->next = point;
            head = newlist;
            return head;
        }
        else if(i==n)  //判断是否在链表尾添加 
        {
            point->next = newlist;
            return head;
        }
        else if(i==x)
        {
            newlist->next = point->next ;
            point->next = newlist;
            return head;
        }
        point = point->next ;
    }
    return head;    
}
int main()
{
    int i,x,n;    
    scanf("%d %d",&n,&x);
    int arr[n];    
    for(i=0;i<n;i++)
    {
        scanf("%d",&arr[i]); 
    }
    //链表的创建
    list *headList = NULL;
    list *arrList = NULL;
    list *head = NULL;
    list *ListAdd = NULL;

    head = headList;  //防止 headList 不为空链表的时候，而导致下面循环链表无头 
    //尾插法 
    for(i=0;i<n;i++)
    { 
        arrList = (list *)malloc(sizeof(list));
        arrList->data = arr[i]; 
        arrList->next = NULL; //将headList放在arrList->next,即arrList的数据是放在headList的前面的 
        //headList=head;
        if(headList == NULL)
        {
            headList = arrList;  //
            head = headList;
        }
        else
        {
            while(headList->next != NULL)
            {
                headList = headList->next ;
            }
            headList->next = arrList;
        } 
    }
    
    ListAdd = addList(head,x,n);
    ptink(ListAdd);
    return 0;
}

#endif