Changes

if _length is zero, it will delete the memory pointed by _data and reallocates enough memory for str and copies the string pointed by str into the newly allocated memory pointed by _data.

Organizes CField objects on the screen, displays them and then lets the user edit them one by one. Most of the code of this class is provided under branches/fardad of the teams' repository. Students are to implement all the add and operator<< methods and operator[] method.