Well, you're only doing this for testtest.length()-1 (the last character in the string). There's no comma there, just the period.
It looks like you are looking for the remove_if algorithm.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.