/in/foo.cc: In function 'int main()':
/in/foo.cc:18:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
/in/foo.cc:23:26: error: 'memcpy' was not declared in this scope
  memcpy(N,num,sizeof(num));
                          ^
/in/foo.cc:31:18: error: 'printf' was not declared in this scope
  printf("%d\n",re);
                  ^