Strictly speaking, the c++ program does not create a Pair class, but instantiates a Pair object that can store two objects as declared as generic types. Is that what you meant? (Otherwise you're looking at static members which doesn't make sense for a pair class).
class Pair
{
public:
int number;
double factor;
};
int main()
{
Pair A;
A.number = 42;
A.factor = 2.6;
return 0;
}