查找中位数出错，问题求解

问题遇到的现象和发生背景

查找中位数时出错

问题相关代码，请勿粘贴截图

//定义学生结构
struct  Student
{
    int sno,sco;
    char gender,major,cno;
};

//从中间逼近
int Partition(struct Student *S,int low,int high)
{
    S[0]= S[low];
    int pivotkey = S[low].sco;
    while(low < high){
        while(low < high && S[high].sco >= pivotkey)   --high;
        S[low] = S[high];
        while (low < high && S[high].sco <= pivotkey)  ++low;
        S[high] = S[low];
    }
    S[low] = S[0];
//    printf("low = %d\n",low);
    return low;
}
void FindMid(struct  student *Sstudents1,int low,int high)
{
    int mid=(low+high)/2;
//    printf("n=%d\t",n);
//    printf("high=%d\t",high);
    while(1){
        int p=Partition(Sstudents1,low,high);
        if(p==mid)
            break;
        else if(p>mid)
            high=p-1;
        else    low=p+1;
    }
    printf("%d",Sstudents1[mid].sco);
}

报错内容

Subscript of pointer to incomplete type 'struct student'

我想要达到的结果

主要问题就是 printf("%d",Sstudents1[mid].sco);报错Sstudents1[mid].sco好像不能这么写，求正确写法或替代方法
感谢

Sstudents1[mid].sco这么写是没什么问题的，看了好一会儿没看出来你这是要实现什么功能？