c++ 读文件操作

ifstream instream;
instream.open("pwd.dat", ios::in || ios::binary);
char buf[64];
while (!instream.eof())
{ 
instream.getline(buf,64);
}
//cout << buf << endl;

instream.close();

FILE *pFile;
fopen_s(&pFile, "pwd.dat", "rb");
if (pFile == NULL)
return -1;
char dest[100];
memset(dest, 0, sizeof(dest));
fread(dest, 100, 1, pFile);
cout << dest << endl;
close(pFile);