First of all, I don't see why would you need to add any elements to your array. This is asked in the title of the question and not confirmed by its body. It's unclear why you cannot just create all elements of fixed sizes.
But if the real question is the one of the title, let's assume you really need to add some elements.
It's a bad idea to add something to an array which is already initialized, no matter "two-dimensional" or not, jagged array or not. This dimension is not "real" and is majorly irrelevant to the problem of adding. Very good explanation of so called "multidimensional arrays" can be found here:
http://www.cplusplus.com/doc/tutorial/arrays[
^].
If you understand this explanation thoroughly, you may also understand that you cannot simply change the size of the memory needed to place additional array elements. You would need to reallocate the array, which, generally, essentially means creation of a brand-new array object with elements copies from the original array; so reallocation can be quite expansive operation. This because the array allocation is based on continuous memory location. With jagged array, the picture is a bit more complex, but each inner array still takes its one room of continuous memory. So, in all cases, you will need additional piece of memory for added elements, which is, generally, may be not available.
You need to use different data structures to implement add/insert/remove operations. As you are using C++, this is not a problem, due to C++ standard library. See, in particular,
std::vector,
std::list:
http://www.cplusplus.com/reference/vector/vector[
^],
http://www.cplusplus.com/reference/list/list[
^].
Also, you can use a
linked list:
http://www.cplusplus.com/articles/LACRko23[
^],
http://cslibrary.stanford.edu/103[
href="http://cslibrary.stanford.edu/103" target="_blank" title="New Window">^].
This CodeProject article can also be useful:
http://www.codeproject.com/Articles/24684/How-to-create-Linked-list-using-C-C.
—SA
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