新建类时出现的有关问题，求教高手到底有什么有关问题

新建类时出现的问题，求教高手到底有什么问题？
以下是头文件中的代码：
class process  
{
private:

typedef struct _CenterInfo
{
int center_x;
int center_y;
int radius;

}
CenterInfo;
 
public:
IplImage* Polar(IplImage*Img1,CenterInfo* centerinfo);

process();
virtual ~process();
  CenterInfo* HoughCircle(IplImage *Img1);//IplImage 是已经定义的一个结构，无错


编译时报错：
F:\学习\创新\VC-OK卡\Sample\MyCapture\process.cpp(35) : error C2143: syntax error : missing ';' before '*'
F:\学习\创新\VC-OK卡\Sample\MyCapture\process.cpp(35) : error C2501: 'CenterInfo' : missing storage-class or type specifiers
F:\学习\创新\VC-OK卡\Sample\MyCapture\process.cpp(36) : error C2501: 'HoughCircle' : missing storage-class or type specifiers
F:\学习\创新\VC-OK卡\Sample\MyCapture\process.cpp(36) : error C2556: 'int *__thiscall process::HoughCircle(struct _IplImage *)' : overloaded function differs only by return type from 'struct process::_CenterInfo *__thiscall process::HoughCircle(stru
ct _IplImage *)'
  f:\学习\创新\vc-ok卡\sample\mycapture\process.h(32) : see declaration of 'HoughCircle'
F:\学习\创新\VC-OK卡\Sample\MyCapture\process.cpp(36) : error C2371: 'HoughCircle' : redefinition; different basic types
  f:\学习\创新\vc-ok卡\sample\mycapture\process.h(32) : see declaration of 'HoughCircle'
执行 cl.exe 时出错.



------解决方案--------------------
typedef struct _CenterInfo
{
int center_x;
int center_y;
int radius;

}CenterInfo,*pCenterInfo;

试试这样定义,并且把private改为public