You have a procedure called determinant that calls itself while in a loop. On top of that it calls make2darray over and over endlessly on entering determinant consuming alot of memory eventually leading to memory errors. Also you never release the dynamic allocation.

You can't have procedures calling itself - it's terrible practice. There's a famous programmers site named after the condition it causes - stackoverflow :)

I'd fix it for you but I don't know enough about your algo. I just need a working polyfit in c++.