/in/foo.cc: In constructor 'Array::Array(int*, int)':
/in/foo.cc:9:17: error: 'memcpy' was not declared in this scope
    9 |                 memcpy(data, arr, sizeof(int) * n);
      |                 ^~~~~~
/in/foo.cc:2:1: note: 'memcpy' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    1 | #include<iostream>
  +++ |+#include <cstring>
    2 | using namespace std;