char变量，不是数组但却被corrupted

在chaxun 这一块一直报错，xuehao被破坏

#include
#include
#define MAX 100
typedef struct student 
{
    char xuehao;
    char name[20];
    double yuwen;
    double math;
};
typedef struct 
{
    student student[MAX];
    int length;
}seqlist;
seqlist luru(seqlist* L)
{
    int n;
    printf_s("请输入学生人数\n");
    scanf_s("%d", &n);
    L->length = n;
    printf_s("请按照学号、姓名、语文成绩、数学成绩的顺序输入\n");
    for (int i = 0; i < n; i++)
    {
        getchar();
        scanf_s("%s", &L->student[i].xuehao,50);
        scanf_s("%s", &L->student[i].name,50);
        scanf_s("%lf", &L->student[i].yuwen);
        scanf_s("%lf", &L->student[i].math);
    }
    return *L;
}
int chaxun(seqlist* L)
{
    int n = L->length;
    char xuehao_1;
    printf_s("请输入想查询学生的学号\n");
    scanf_s("%s", &xuehao_1,50);
    for(int i=0;iif (xuehao_1 == L->student[i].xuehao)
        {
            printf_s("%s\n", L->student[i].name);
            printf_s("%.1lf\n", L->student[i].math);
            printf_s("%.1lf\n", L->student[i].yuwen);
            return 1;
        }
    printf("请查询正确后重试\n");
    return NULL;
    
}
void  tongji(seqlist *L)
{
    double  sum_1=0, sum_2=0;
    for (int i=0; i < L->length; i++)
        sum_1 = sum_1+L->student[i].math;
    printf_s("数学成绩平均分为 %.1lf\n",sum_1 / L->length);
    for (int i=0; i < L->length; i++)
        sum_2 = sum_2+L->student[i].yuwen;
    printf_s("数学成绩平均分为 %.1lf\n",sum_2 / L->length);

}
int menu_select()
{
    int i;
    printf_s("1.录入\n");
    printf_s("2.查询\n");
    printf_s("3.统计\n");
    printf_s("4.退出\n");
    do 
    {
       scanf_s("%d",&i);
       return i;
    } while (i < 5 && i>0);
}

int main()
{
    seqlist* L;
    L = (seqlist*)malloc(sizeof(seqlist));
    for (;;)
    {
        switch (menu_select())
        {
        case 1:
            luru(L);
            break;
        case 2:
            chaxun(L);
            break;
        case 3:
            tongji(L);
            break;
        case 4:
            exit ;
        }
    }
}

typedef struct student 
{
    char xuehao[50];
    char name[50];
    double yuwen;
    double math;
}

int chaxun(seqlist* L)
{
    int n = L->length;
    char xuehao_1[50];
    printf_s("请输入想查询学生的学号\n");
    scanf_s("%s", &xuehao_1,50);
    for(int i=0;i<n;i++)
        if (strcmp(xuehao_1, L->student[i].xuehao) == 0)
        {
            printf_s("%s\n", L->student[i].name);
            printf_s("%.1lf\n", L->student[i].math);
            printf_s("%.1lf\n", L->student[i].yuwen);
            return 1;
        }
    printf("请查询正确后重试\n");
    return NULL;
    
}