Dynamic allocation basic(help)

Question

what is benefit of dynamic allocation on this code.I can get user input at run time and print the output.in this program whether memory is deleted or not after close the program .
https://code.sololearn.com/ctteq9dGFx3n/?ref=app

Answer 1

Note that some compilers do not allow variables in place of array size for array declaration.
int a[n];
Instead:
int* a = new int[n];
is universally accepted.

Answer 2

Dynamic allocation, for this kind of code, is great when you dont know how many elements the user wants to input.