#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

加上 main 函数
我编译没错啊？？？
我用的是VS2010.

没有main()函数入口，怎么编译啊

单独一个类，好像也能编译呀，如果这个类是要被其他函数调用的话，那又怎么加main函数呢？

main()
{
}

请问sample(){data = 10;}写在那是什么意思？请教~

能用main（）函数调用一个main（）函数吗？为什么？一个程序不是只有一个main（）函数吗？

默认的构造函数，构建对象时可以不赋初值

有隐含的非法字符把，你把那一行全部删除从新写在试试。
还有，这个构造函数设为私有唯一目的是避免别人用
Sample s；
这样的方式来使用你的类，你根本不需要在函数体在写上任何代码。