#include <iostream>

using namespace std;
class Sample ;

class Sample

{

private:

  int data;

  Sample( ){data=10;}

public:

  Sample(int d){data=d;}

   operator int( ){return data;}


};

--------------------Configuration: training - Win32 Debug--------------------
Compiling...
training.cpp
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(12) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(12) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(12) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(12) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(14) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(14) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(14) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(14) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(18) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(18) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(18) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(18) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(20) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(20) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(20) : error C2018: unknown character '0xa1'
D:\Program Files\Microsoft Visual Studio\MyProjects\myproject\training.cpp(20) : error C2018: unknown character '0xa1'
执行 cl.exe 时出错.

training.obj - 1 error(s), 0 warning(s)

#include <iostream>

using namespace std;
class Sample ;

class Sample

{

private:

  int data;

  //Sample( ){data=10;}

public:

  Sample(int d){data=d;}

   operator int( ){return data;}


};

改为上面的，就好了