∥ SDCLS.H class x t nt d static int n Count: public X(int a=0): d(a)t nCount ++ y 0 n Count void Set(int a d=a;} int Geto return d Counto return nCount int X:: nCount =0// SDCLS.H class X { int d; static int nCount; public: X(int a = 0) : d(a) { nCount ++; } ~X() { nCount --; } void Set(int a) { d = a; } int Get() { return d; } int Count() { return nCount; } }; int X :: nCount = 0;