How does memory allocation work for two-dimensional arrays?

Memory allocation for two-dimensional arrays is typically done in a row-major or column-major order, depending on the language.

In a two-dimensional array, data is stored in a tabular form with rows and columns. The memory allocation for such arrays is not a straightforward process as it might seem. It's not like a single block of memory is allocated for the entire array. Instead, the memory is allocated in a specific order, either row-major or column-major, depending on the programming language being used.

In row-major order, the entire first row of the array is stored first, followed by the second row, and so on. This means that elements of the same row are stored in contiguous memory locations. This is the method used by programming languages like C and C++.

On the other hand, in column-major order, the entire first column is stored first, followed by the second column, and so on. This means that elements of the same column are stored in contiguous memory locations. This is the method used by programming languages like Fortran.

The reason for these different methods of memory allocation is due to the way these languages access array elements. In C and C++, arrays are accessed row by row, so it makes sense to store elements of the same row together. In Fortran, arrays are accessed column by column, so it makes sense to store elements of the same column together.

It's also worth noting that a two-dimensional array is essentially an array of arrays. This means that each row (or column, depending on the language) is a separate array, and the two-dimensional array is an array that holds these separate arrays. This is why the memory allocation for two-dimensional arrays is done in the way it is.

Understanding how memory allocation works for two-dimensional arrays is crucial for writing efficient code. By knowing how your programming language of choice stores array elements, you can write code that accesses these elements in the most efficient way possible.