"To continue with the development of a program..."
you should fix the part of your code that created lots of variables like that, so that they are all conveniently in one cell array C. Then your task is trivially easy:
cat(1,C{:})
By designing your data better, you can make your code much simpler, more efficient, and less buggy!
When beginners write code that requires accessing variable names dynamically, they force themselves into writing slow, complex, buggy code that is hard to debug. Which is why the MATLAB documentation specifically recommends avoiding doing this: "A frequent use of the eval function is to create sets of variables such as A1, A2, ..., An, but this approach does not use the array processing power of MATLAB and is not recommended. The preferred method is to store related data in a single array."
So the best solution is fix the code where those variables are created. I doubt that you sat and wrote them all out by hand, so probably they were created by importing some data from some files, in which case it is trivial to fix using a cell array and indexing. Another tip is to always load data into a variable:
S = load(...)
because this makes processing the data much simpler and reduced the risk of bugs.
In any case, it is much better fix the variables where you create/load them so that they are stored in a simple cell array, rather than trying to write slow hack code later.
