I didn't try the code by myself, but using such a big array as a local variable doesn't sound like a very good idea. You also don't do any boundary checks when reading into the file. This may corrupt your stack and lead to unpredictable results.
In mergesort, you have written int mid=0. Instead do this.
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.