为什么它会打印重复的两份信息
//读取学生信息
void Readstudent()
{
 //打开文件
 FILE* fp;
 errno_t err = fopen_s(&fp, "D:\\stuinf.txt", "r");
 if (fp == nullptr)
 {
  cout << "打开文件失败" << endl;
  return;
 }
 //读文件
 student stu;
 while (fread(&stu, 1, sizeof(student), fp))
 {
  //创建一个新节点
  Node* pNewNode = (Node*)malloc(sizeof(Node));
  pNewNode->pNext = nullptr;

  memcpy(pNewNode, &stu, sizeof(student));
  //头插法
  if (g_pHead == nullptr)
  {
   g_pHead = pNewNode;
  }
  else {
   pNewNode->pNext = g_pHead;
   g_pHead = pNewNode;
  }

 }