/in/foo.cc: In function 'int main()':
/in/foo.cc:31:23: error: invalid conversion from 'int*' to 'int' [-fpermissive]
   memset(0,p,sizeof(p));
                       ^
In file included from /usr/include/c++/6/cstring:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:48,
                 from /in/foo.cc:1:
/usr/include/string.h:62:14: note:   initializing argument 2 of 'void* memset(void*, int, size_t)'
 extern void *memset (void *__s, int __c, size_t __n) __THROW __nonnull ((1));
              ^~~~~~
/in/foo.cc:31:23: warning: null argument where non-null required (argument 1) [-Wnonnull]
   memset(0,p,sizeof(p));
                       ^