Can You Overload the [] Operator Twice to Create a Two-Dimensional Array in C ?

Overloading the [] Operator for Two-Dimensional Arrays

Operator overloading allows programmers to extend the functionality of existing operators to create custom behaviors for their classes and objects. One common use case is to overload the [] operator for accessing elements of an array. However, is it possible to overload the [] operator twice, effectively creating a two-dimensional array?

Double Overloading of [] Operator

Yes, it is possible to overload the [] operator multiple times to achieve a two-dimensional array behavior. By defining one [ ] operator to return an object that itself can handle [ ] indexing, you can create a nested array-like structure.

Example Code

Consider the following code sample:

class ArrayOfArrays {
public:
    ArrayOfArrays() {
        _arrayofarrays = new int*[10];
        for(int i = 0; i < 10; ++i)
            _arrayofarrays[i] = new int[10];
    }

    class Proxy {
    public:
        Proxy(int* _array) : _array(_array) { }

        int operator[](int index) {
            return _array[index];
        }
    private:
        int* _array;
    };

    Proxy operator[](int index) {
        return Proxy(_arrayofarrays[index]);
    }

private:
    int** _arrayofarrays;
};

In this code, the ArrayOfArrays class represents a two-dimensional array. The [ ] operator is overloaded twice:

1. The first overload returns a Proxy object when provided with an index.
2. The Proxy class overloads the [ ] operator again to retrieve elements from the underlying array.

Usage

To use the ArrayOfArrays class, you can index it twice as if it were a regular two-dimensional array:

ArrayOfArrays aoa;
aoa[3][5];  // Access the element at row 3, column 5

This code will first invoke the [ ] operator on the ArrayOfArrays instance, which will return a Proxy object for row 3. Then, it will invoke the [ ] operator on the Proxy object, which will return the element at column 5 in row 3.

By implementing double overloading of the [ ] operator, you can simulate the behavior of two-dimensional arrays and create nested structures for more complex data storage and retrieval scenarios.

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