C语言----使用链表实现的客户管理系统

实现一个客户信息管理系统，功能包括添加客户、修改客户、删除客户、显示客户列表。
学完了C语言和链表没事情干拿出来写一写，检测下学习成果

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Node
{
    int num;
    char name[20];
    char gender;
    char year;
    char phone[14];
    char email[30];
    struct Node *next;
} people;
typedef struct Head // 头指针
{
    people *next;
} list;
void Initlinkedlist(list *p) // 初始化链表
{
    p->next = NULL;
}
void AddPeoplelinkedlist(list *head) // 添加成员，尾插
{
    printf("\n--------------添加成员--------------");
    people *p = head->next;
    people *q;
    if (p == NULL)
    {
        q = (people *)malloc(sizeof(people));
        if (q == NULL)
        {
            printf("err");
            exit(0);
        }
        printf("\n请输入姓名:");
        getchar();
        scanf("%s", q->name);
        printf("\n请输入性别:");
        getchar();
        scanf("%c", &q->gender);
        printf("\n请输入年龄:");
        getchar();
        scanf("%c", &q->year);
        printf("\n请输入电话号码:");
        getchar();
        scanf("%s", q->phone);
        printf("\n请输入电子邮箱:");
        getchar();
        scanf("%s", q->email);

        q->num = 1;
        head->next = q;
        q->next = NULL;
    }
    else
    {
        q = (people *)malloc(sizeof(people));
        if (q == NULL)
        {
            printf("err");
            exit(0);
        }
        printf("\n请输入姓名:");
        getchar();
        scanf("%s", &q->name);
        printf("\n请输入性别:");
        getchar();
        scanf("%c", &q->gender);
        printf("\n请输入年龄:");
        getchar();
        scanf("%c", &q->year);
        printf("\n请输入电话号码:");
        getchar();
        scanf("%s", &q->phone);
        printf("\n请输入电子邮箱:");
        getchar();
        scanf("%s", &q->email);
        while (p->next != NULL)
        {
            p = p->next;
        }
        q->num = p->num + 1;
        p->next = q;
        q->next = NULL;
    }
}
void TraverseLinkedList(list *head) // 遍历打印
{
    people *q;
    q = head->next;
    printf("\n--------------客户列表--------------");
    printf("\n编号\t\t姓名\t\t性别\t\t年龄\t\t电话\t\t邮箱");
    while (q != NULL)
    {

        printf("\n%d", q->num);
        printf("\t\t%s", q->name);
        printf("\t\t%c", q->gender);
        printf("\t\t%c", q->year);
        printf("\t\t%s", q->phone);
        printf("\t\t%s", q->email);
        q = q->next;
    }
}
void deleteLinkedList(int n, list *q) // 删除元素
{
    people *t, *p;
    int data;
    p = q->next;
    if (n > 1)
    {
        for (; (p->next)->num != n;)
        {
            p = p->next;
        }
        t = p->next;
        p->next = t->next;
        free(t);
        printf("删除成功");
    }
    if (n == 1)
    {

        t = q->next;
        q->next = t->next;
        free(t);
        printf("删除成功");
    }
}
void changeLinkedlist(int n, list *q) // 修改元素
{
    people *t, *p;
    int data;
    p = q->next;
    if (n > 1)
    {
        for (; (p->next)->num != n;)
        {
            p = p->next;
        }
        p = p->next;
        printf("\n请输入姓名:");
        getchar();
        scanf("%s", p->name);
        printf("\n请输入性别:");
        getchar();
        scanf("%c", &p->gender);
        printf("\n请输入年龄:");
        getchar();
        scanf("%c", &p->year);
        printf("\n请输入电话号码:");
        getchar();
        scanf("%s", p->phone);
        printf("\n请输入电子邮箱:");
        getchar();
        scanf("%s", p->email);
        printf("修改成功");
    }
    if (n == 1)
    {
        printf("\n请输入姓名:");
        getchar();
        scanf("%s", p->name);
        printf("\n请输入性别:");
        getchar();
        scanf("%c", &p->gender);
        printf("\n请输入年龄:");
        getchar();
        scanf("%c", &p->year);
        printf("\n请输入电话号码:");
        getchar();
        scanf("%s", p->phone);
        printf("\n请输入电子邮箱:");
        getchar();
        scanf("%s", p->email);
        printf("修改成功");
    }
}
void menu(list *customer) // 菜单显示
{
    while (1)
    {
        int i, n;
        char flag;
        printf("\n--------------客户信息管理软件--------------");
        printf("\n\t\t1添加客户");
        printf("\n\t\t2修改客户");
        printf("\n\t\t3删除客户");
        printf("\n\t\t4客户列表");
        printf("\n\t\t5退出\n请输入1-5:");
        scanf("%d", &i);
        switch (i)
        {
        case 1:
            AddPeoplelinkedlist(customer);
            break;
        case 2:
            printf("\n输入要修改的客户的编号(-1退出):");
            scanf("%d", &n);
            if (n == -1)
            {
                break;
            }
            else
            {
                changeLinkedlist(n, customer);
            }
            break;
        case 3:
            printf("\n输入要删除的客户的编号(-1退出):");
            scanf("%d", &n);
            if (n == -1)
            {
                break;
            }
            else
            {
                deleteLinkedList(n, customer);
            }
            break;
        case 4:
            TraverseLinkedList(customer);
            break;
        case 5:
            printf("是否确认要退出（Y或N）: ");
            getchar(); // 过滤回车
            scanf("%c", &flag);
            if (flag == 'Y' || flag == 'y')
            {
                printf("已退出");
                exit(0);
            }
            if (flag == 'N' || flag == 'n')
            {
                break;
            }
        default:
            printf("请输入1-5的值！");
            break;
        }
    }
}
void main()
{
    list *customer;
    customer->next = NULL;
    Initlinkedlist(customer);
    menu(customer);
}