/in/foo.cc: In function 'int main()':
/in/foo.cc:23:15: warning: the address of 'void print_a()' will never be NULL [-Waddress]
   23 |         cout<<print_a;
      |               ^~~~~~~
/in/foo.cc:4:6: note: 'void print_a()' declared here
    4 | void print_a()
      |      ^~~~~~~