C语言创建链表程序运行没有结果

Question

#include <stdio.h>
#include <stdlib.h>
#define count 5
typedef struct Linklist
{
    int data;
    struct Linklist *next;
}L;
L *head = NULL,*tail=NULL;
int main()
{
    int n;
    L *p = (L*)malloc(sizeof(L));
    p->data = 1;
    head->next = p;
    tail = p;
    tail->next = NULL;
    /*tail = p;
    p->next = NULL;*/
    for (int i = 0; i < count; i++)
    {
        printf("Please input a number:");
        scanf("%d",&n);
        p = (L*)malloc(sizeof(L));
        p->data = n;
        tail->next = p;
        tail = p;
        p->next = NULL;
    }
    printf("Data is done!!");
    head = head->next;
    while (head!=NULL)
    {
        printf("%d ",head->data);
    }
    return 0;
}

这个代码用于创建一个链表,可是使用VSCode运行没有结果,这是怎么回事呢？听劝！！

Answer 1

错的地方我注释出来了

#include <stdio.h>
#include <stdlib.h>
#define count 5
typedef struct Linklist
{
    int data;
    struct Linklist *next;
}L;
L *head = NULL,*tail=NULL;
int main()
{
    int n;
    head=(L*)malloc(sizeof(L));//头指针没初始化
    L *p = (L*)malloc(sizeof(L));
    p->data = 1;
    head->next = p;
    tail = p;
    tail->next = NULL;
    /*tail = p;
    p->next = NULL;*/
    for (int i = 0; i < count; i++)
    {
        printf("Please input a number:");
        scanf("%d",&n);
        p = (L*)malloc(sizeof(L));
        p->data = n;
        tail->next = p;
        tail = p;
        p->next = NULL;
    }
    printf("Data is done!!");
    head = head->next;
    while (head!=NULL)//输出时指针没有后移
    {
        printf("%d ",head->data);
        head=head->next;//指针后移
    }
    return 0;
}