How to Convert a 2D Array to a Pointer-to-Pointer in C ?

Converting a 2D Array to a Pointer-to-Pointer

Consider the following scenario:

Activity solution[a][b];
// ...
Activity **mother = solution;

In this situation, you may desire to convert a 2D object array into a pointer-to-pointer. However, direct conversion is not possible due to the incompatibility of types.

Introducing an Intermediate Array

To bridge the gap, introduce an intermediate "row index" array:

Activity solution[a][b];

Activity *solution_rows[a] = { solution[0], solution[1] /* and so on */ };

Activity **mother = solution_rows;

This allows you to access elements in the following manner:

mother[i][j] = solution[i][j]

Understanding the Conversion

solution[i] is a pointer to the i-th row of the 2D array. solution_rows is an array of these row pointers. Therefore, solution_rows[i] is equivalent to solution[i].

When you assign solution_rows to mother, you effectively create a pointer-to-pointer that points to the first elements of each row in solution.

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