Why can't we give input directly to pointer array?

Question

I have created pointer array. In which, I can store data(string in mentioned program) by using 1.assignment operator
or
2. by creating new data variable -> taking input by using cin -> assigning new data variable to old one.
X But why I can't use cin directly for pointer array to store data.
as :
cin >> a; //assume a as pointer array.

https://code.sololearn.com/cMPN1Zw27Ego/?ref=app