关于模版的实参演绎

关于模版的实参推演
template<class T>
void fun1(T a)
{
T x,y;
cout<<typeid(T).name()<<endl;
cout<<typeid(a).name()<<endl;
}


template<class T>
void fun2(T *a)
{
//T x,y;
//T x=0,y=0;
cout<<typeid(T).name()<<endl;
cout<<typeid(a).name()<<endl;
}


template<class T>
void fun3(const T *a)
{
T x,y;
cout<<typeid(T).name()<<endl;
cout<<typeid(a).name()<<endl;
}
void main()
{
int a = 10;
const int b = 20;
int *ip = &a;
const int *cp = &b;


//fun1(a);      //int int
//fun1(b);      //int int 
//fun1(&a);   //int * int *
//fun1(&b);   //int const * int const *
//fun1(ip);     //int * int *
//fun1(cp);    //int const *  int const *
//fun1(&ip);  //int **  int **
//fun1(&cp);  //int const ** int const **


//fun2(a);        //出错
//fun2(b);        //出错
//fun2(&a);     //int  int *
//fun2(&b);     //int       int const *
//fun2(ip);       //int   int *
//fun2(cp);         //int       int const *
//fun2(&ip);    //int *   int **
//fun2(&cp);    //int const *   int const **


//fun3(a);        //出错
//fun3(b);        //出错
//fun3(&a);     //int   int const *
//fun3(&b);     //int       int const *
//fun3(ip);       //int   int const *
//fun3(cp);         //int       int const *
//fun3(&ip);    //int *   int *const *
//fun3(&cp);    //int const *   int const *const*
}