Arrays are simple but quite powerful constructs in C/C++. They are merely a representation of consecutive data in memory.

They don’t contain any meta data (like size). But since they are stored in memory in such a simple manner processors can handle them very efficiently.

//     rows  columns
//        |  |
//        v  v
char data[3][2]={{0,1},
                 {2,3},
                 {4,5}};

The values of the array data are stored row for row in memory:

0,1,2,3,4,5

Another possibility to see it is that multi-dimensional arrays in C/C++ are arrays of arrays.

So data is like an array (with size 3) of arrays of char (with size 2).

Here is a good explanation.

The same applies to more than 2 dimensions.