#include <iostream> #include <cmath> #include <iomanip> using namespace std; class Function { protected: double x, y; public: Function() { x = 0; y = 0; } Function(Function& p) { x = px; y = py; } virtual double Calculation(int) = 0; }; class sin_cos : public Function { sin_cos(): Function() {} virtual double Calculation(int t) { y = sin(t); x = cos(t); return x; } }; int main() { setlocale(LC_ALL, "rus"); Function* mas[5]; mas[1] = new sin_cos; cout << mas[i]->Calculation(10) << endl; system("pause"); return 0; }
  • And how to fix the "impossible to access private member"? - Valery
  • Make it public :) - Harry
  • Oh, yes, inattention) - Valery

2 answers 2

It would be necessary as a comment, but it does not fit there ...
VC ++ writes the following:

error C2248: sin_cos :: sin_cos: it is impossible to access the private member declared in the class "sin_cos"

error C2065: i: undeclared identifier

error C2227: the expression to the left of "-> Calculation" should indicate the type of a class, structure or union, or a universal type

What exactly is this incomprehensible to you?

GCC swears about the same :

 prog.cpp: In function 'int main()': prog.cpp:40:18: error: 'sin_cos::sin_cos()' is private within this context mas[1] = new sin_cos; ^~~~~~~ prog.cpp:26:5: note: declared private here sin_cos(): Function() ^~~~~~~ prog.cpp:41:17: error: 'i' was not declared in this scope cout << mas[i]->Calculation(10) << endl;

sin_cos - the constructor in the class is not declared as public , so create an object like this

 mas[1] = new sin_cos;

no - no access rights. And then you can not use

 mas[i]->Calculation(10)

because not only the value of i unknown, but this variable itself is not declared.

    You forgot to specify public access control for the sin_cos class sin_cos and the Calculation virtual function

     class sin_cos : public Function { public: ^^^^^^^ sin_cos(): Function() {} virtual double Calculation(int t) { y = sin(t); x = cos(t); return x; } };

    Also in main, I think you meant index 1 instead of variable i, which is not declared

      mas[1] = new sin_cos; cout << mas[1]->Calculation(10) << endl; ^^^

    Keep in mind that array indices start at 0, not at 1.