How can i call the data type from the function of a class

[cxlzmkm]

Hello, everyone.
I defined a class as well as member function. And now i would like to call the data type(x.dat) imported from outside.
how could I do that? Thank you very much in advance.

Sorry, I have no codes. But it would be sth like this:

class abs{
private:

public:
void function(data){     //here i would like to use the external data  x.dat
...
}
}

[LB]

I'm not sure what you mean? Could you try rephrasing or providing a better example?