How to use mir functions on a lot of sound files using a loop and getting the values in a matrix ?

I have been trying to simplify the manual work of using each mir function on the no. of soundtracks that i have, therefore i though of naming the soundtracks in numericals alone i.e 1.wav, 2.wav, 3.wav.....What i want now is to get an array of results with no. 1no. of files on the horizontal rows and each vertical coloumns dedicated to one mir function (scalar o/p). The problem im facing is that the 'n.wav' doesnt open for eg. if n=3(which has been converted to a string format using num2str function) at that loop, 3.wav but instead searches for 'n.wav' named file. How do I input strings for names of files