The overloaded operator[ ]( ) function returns the value of the array as indexed by the value of its parameter. : overload bracket operator « Operator Overloading « C++ Tutorial

1. C++ Tutorial
2. Operator Overloading
3. overload bracket operator

#include <iostream>
using namespace std;
   
class MyClass {
  int a[3];
public:
  MyClass(int i, int j, int k) {
    a[0] = i;
    a[1] = j;
    a[2] = k;
  }
  int operator[](int i) { return a[i]; }
};
   
int main()
{
  MyClass ob(1, 2, 3);
   
  cout << ob[1]; // displays 2
   
  return 0;
}