How Can I Effectively Simulate Statically Declared 2D Arrays as Class Members in C ?

Statically Declared 2-D Arrays as Class Member Data in C

Within object-oriented programming, developers often encounter the need to create multidimensional arrays as class member data. In C , a common challenge arises when attempting to statically declare such arrays, especially when aiming to avoid the potential drawbacks of dynamic memory allocation.

To address this challenge, some developers prefer to utilize contiguous memory allocation to minimize cache misses. While it is not explicitly possible to statically declare a 2-D array as a class member, a technique using a vector of integers and operator overloading can emulate this functionality. This approach leverages the contiguity of the vector and provides a way to index the elements as if they were in a 2-D array.

An example of this technique is provided below:

class Array2D {
public:
    vector<int> v;
    int nc;
    Array2D(int NR, int NC) : v(NR * NC), nc(NC) {}
    int *operator[](int r) { return &v[r * nc]; }
};

int main() {
    Array2D array2d(2, 3);
    array2d[0][0] = 1;
    array2d[1][2] = 6;
}

In this code, the vector v acts as the underlying storage for the 2-D array. The class constructor initializes the vector with the specified number of rows and columns. The operator[] function provides a convenient way to access and modify elements by using row and column indices.

This technique effectively mimics the behavior of a statically declared 2-D array while maintaining the benefits of contiguous memory allocation. It is a viable solution for situations where performance considerations, such as cache misses, need to be prioritized.

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