OOP C++ language

I started learning OOP in C++. I try to solve a task like this:

Create a class - a list based on a one-size-fits-all array of integers. Assign a constructor, a destructor, the functions of adding an element to the top (end) of the list, selecting an element from the list by number, sorting the list, showing the elements of the list to the top and to the bottom of the list."

In the delete function, the compiler constantly knocks out the same error:

E0852 the expression must be a pointer to the full type of the object My_4_Project C:\Users\artem\source\repos\Project4\My_4_Project\Source.cpp

Here is my code:

#include <iostream>
#include <algorithm>

using namespace std;

class Array {
  private:
    int* a;
    unsigned int size;
    int b, c = 0, d;
  public:
    Array();
    Array(int s);
    ~Array();
    int& operator[](int index);
    void setarray();
    void getarray();
    void add();
    void delet();
    void sort();
};

Array::Array() {
   size = 10;
   a = new int[size];
   for (size_t i = 0; i != size; i++) {
         a[i] = 0;
   }
}
Array::Array(int s) {
   if (s > 0) {
       size = s;
       a = new int[size];
       for (size_t i = 0; i != size; i++) {
           a[i] = 0;
       }
   }
   else cout << "Size can't be negativ";
}
Array::~Array() {
   delete[]a;
}
int& Array::operator[](int index) {
    if (index <= size) {
        return a[index];
    }
}
void Array::setarray() {
    for (size_t i = 0; i != size; i++) {
          cin >> a[i];
    }
}
void Array::getarray() {
    for (size_t i = 0; i != size; i++) {
        cout << a[i] << " ";
    }
}
void Array::add()
{
     /* ? ? ? */ ;
}
void Array::delet() {
    cin >> b;
    for (int i = 0; i < size; i++)
    {
        if (b == a[i])
            c++;
        if (c > 2) delete a[i];
    }
    cout << c;
}
void Array::sort() {
    int temp;

    for (int i = 0; i < size - 1; i++) {
        for (int j = 0; j < size - i - 1; j++) {
            if (a[j] > a[j + 1]) {
               temp = a[j];
               a[j] = a[j + 1];
               a[j + 1] = temp;
            }
        }
    }
    for (int i = 0; i < size; i++) {
        cout << a[i] << " ";
    }
}

int main() {
    cout << "Enter 10 number`s massive: ";
    Array arr(10);
    arr.setarray();
    cout << endl;
    arr.getarray();
    cout << endl;
    cout << "Sorted massive: ";
    arr.sort();
    cout << endl;
    cout << "Witch symbol you wanna delete?: ";
    arr.delet();
    return 0;
}