C++ Dynamic Constructor -

i'm getting error:

no operator "[]" matches these operands

for line:

cout << a[j].display(n) 

but when take out [j], i'm getting error:

class "list" has no member "display"

here code:

class list { protected:     int *p; // pointer list     int size; // dimension public:     list(int x)     {         size = x;         p = new int[size];      }     void get(int i, int val)     {         p[i] = val;     } };  class dlist : public list { public:     int display(int i)     {         return p[i];     } };  int main() {     int n;     cout << "enter elements in row\n";     cin >> n;      list a(n);      int j, val;     (j = 0; j < n; j++)     {         cin >> val;         a.get(j, val);     }     cout << "\n";     cout << "list of elements :\n";     cout << "----------------------\n";     (j = 0; j < n; j++)         cout << a[j].display(j) << "\t";      cout << "\n";     return 0; } 

please help!

the class list indeed has no member function display. class dlist declared like

class dlist : public list //... 

has such member function. object a defined in main object of class list

list a(n); 

moreover can not create object of type dlist because have define explicitly constructor of type.

if want use polymorphism introduce virtual functions making example member function display virtual.

also syntax

cout << a[j].display(j) << "\t";         ^^^^^^^^^^^^^^ 

is incorrect because object a scalar object. not array of objects , class has no overloaded operator [].

you should start defining explicitly virtual destructor (otherwise there can memory leak in program) delete dynamically allocated memory in constructor parameter, copy constructor , copy assignment operator in class list. can define subscript operator , on.