How Can I Overload the [] Operator for Accessing Elements in a Two-Dimensional Array in C ?

Overloading the [] Operator for Two-Dimensional Arrays

A two-dimensional array is a collection of elements organized into rows and columns. In C , two-dimensional arrays are typically stored as a pointer to an array of pointers, with each pointer pointing to an array of elements in a row.

Overloading the [] Operator

In C , it is possible to overload the [] operator to access elements of an array. By default, the [] operator takes a single integer index and returns a reference to the corresponding element in the array.

Overloading for Two Dimensions

To allow for accessing elements of a two-dimensional array using two indices, we can overload the [] operator twice. This can be done by creating a nested class that represents a row of the array, and then overloading the [] operator for both the parent class and the nested class.

Example Code

Here is an example implementation of a two-dimensional array class with overloaded [] operators:

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 example, the ArrayOfArrays class represents the entire two-dimensional array, while the Proxy class represents a row of the array. The [] operator is overloaded in both the ArrayOfArrays and Proxy classes, allowing elements to be accessed using one or two indices, respectively.

Usage

To use the ArrayOfArrays class, you can create an instance and access elements using the [] operators:

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

By overloading the [] operator in this way, we can access elements of a two-dimensional array using a syntax that is similar to accessing elements of a one-dimensional array.

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