#include <iostream>
class One
{
public:
int data;
One(){data = 99;};
};
class Another
{
public:
Another(){};
int function(One* );
};
int Another::function(One* one) // <-- possibly Another:: missing?
{
return one -> data;
}
int main()
{
One one;
Another another;
std::cout << another.function(&one) << '\n';
}