链表输出结果最后一行乱码

Question

链表输出最后一行数据总是乱码
这个输出链表的函数有什么问题吗

void display(student* head)
{
    student* p = head;
    if (!p)
    {
        printf("链表为空!\n");
        exit(1);
    }
    else
        while (p)
        {
            printf("%-20s %-12lld\n", p->name, p->nmber);
            p = p->next;
        }
}

这里是完整代码

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

typedef struct stu
{
    long long nmber;
    char name[10];
    struct stu* next;
}student;

student* init()
{
    return NULL;
}

student* get_num(student* head)
{
    int flag;
    head = (student*)malloc(sizeof(student));
    student* q, * p = head;
    p->next = NULL;
    printf("请输入第一个同学的数据(姓名、手机号)\n");
    char nam[10];
    int i = 2;
    flag = scanf_s("%s", nam,10);
    while (i<3)
    {

        scanf_s("%lld", &p->nmber);
        strcpy_s(p->name, nam);
        printf("请输入第%d个同学的信息:\n", i++);
        flag = scanf_s("%s", nam,10);
        if (flag == 1)
        {
            q = (student*)malloc(sizeof(student));
            q->next = NULL; p->next = q; p = q;
        }
        else break;
    }
    return head;
}
student* insert(student* head, int position)
{
    int flag;
    char nam[10];
    student* p = head, * q = NULL;
    if (position < 1)
    {
        printf("输入位置有误！");
        exit(1);
    }
    q = (student*)malloc(sizeof(student));
    printf("请输入增加的学生的姓名、手机号:\n");
    flag = scanf_s("%s", nam,10);
    scanf_s("%lld", &q->nmber); q->next = NULL;
    if (flag == 1)
        strcpy_s(q->name, nam);
    if (position == 1)
    {
        if (!p)
        {
            printf("通讯录为空！\n");
            exit(1);
        }
        else
        {
            q->next = p; return q;
            printf("插入成功!\n");
        }
    }
    else
    {
        for (int i = 1; p; i++)
        {
            if (i + 1 == position)
            {
                q->next = p->next;
                p->next = q;
                printf("插入成功!\n");
                return head;
            }
        }
        if (!p)
        {
            printf("未找到增加的位置！\n");
            return head;
        }
    }
}
student* del(student* head, int position)
{
    student* p = head, * q = NULL;
    if (!p)
    {
        printf("删除失败，链表为空！\n");
    }
    if (position < 1)
    {
        printf("删除失败，输入的位置有误！\n");
        return head;
    }
    if (position == 1)
    {
        if (p->next)
        {
            q = p;
            head = p->next;
            free(q);
            return head;
        }
        printf("删除成功！\n");
    }
    for (int i = 1; p; i++)
    {
        if (i + 1 == position && p->next)
        {
            q = p->next;
            p->next = p->next->next;
            free(q);
            return head;
        }
        p = p->next;
        printf("删除成功!\n");
    }
    if (!p)
    {
        printf("删除失败，该位置处无元素！\n");
    }
}
void display(student* head)
{
    student* p = head;
    if (!p)
    {
        printf("链表为空!\n");
        exit(1);
    }
    else
        while (p)
        {
            printf("%-20s %-12lld\n", p->name, p->nmber);
            p = p->next;
        }
}

int main()
{
    int order, position;
    student* head = init();
    head = get_num(head);
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
    getchar();
loop:
    printf("—————————请输入操作—————————\n1.插入一个新信息，2.删除一个信息,3.输出所有信息 ：\n");
    getchar();
    scanf_s("%d", &order);
    switch (order)
    {
    case 1:
        printf("请输入要插入的节点位置:\n");
        scanf_s("%d", &position);
        head = insert(head, position);
        break;
    case 2:
        printf("请输入要删除节点的值:\n");
        scanf_s("%d", &position);
        head = del(head, position);
        break;
    case 3:
        printf("输出结果为:\n");
        display(head);
        break;
    default:printf("ERROR\n");
    }
    goto loop;
}

Answer 1

截图看一下你外面怎么塞这个 链表数据的
我测试是可以的

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

typedef struct Student
{
    char name[20];
    
    long int number;
 
    struct Student *next; //指针域
} student;

void display(student* head);

int main()
{
    student* headNode = (student*)malloc(sizeof(student));
    strcpy(headNode->name, "hello");
    headNode->number = 12345678911;
    
    student* stu = (student*)malloc(sizeof(student));
    strcpy(stu->name, "world");
    stu->number = 98765432111;
    
    headNode->next = stu;
    
    display(headNode);
    return 0;
}

void display(student* head)
{
    student* p = head;
    if (!p)
    {
        printf("链表为空!\n");
        exit(1);
    }
    else
        while (p)
        {
            printf("%-20s %-12lld\n", p->name, p->number);
            p = p->next;
        }
    return;
}

PS: 第二个节点的 成员列表没有赋值，所以输出 都是随机的数

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