View Compilation Error

0_0_30306695_18263.cpp: In function 'int main()':
0_0_30306695_18263.cpp:55:36: error: cannot pass objects of non-trivially-copyable type 'std::string {aka class std::basic_string<char>}' through '...'
   printf("Case #%d: %s\n", ans[flag]);
                                    ^