27 and 28 are illegal in standard c++. variable length array. again on 54
apart from those, can you tell us in detail what the problem is? Eg "it inserts in the wrong place" or "it crashes" or whatever?
standard string has an insert. Is your homework to mix c++ and C style strings the hard way? Or did you need to see how to do this in c++ without all the weirdness?
Well first, some info re what the code is supposed to do would be sort of helpful. Then say something about what the problem with the code is, then mention what debugging has been done to try to find the issue in the code - leading to a specific c++ question.