View Compilation Error

0_0_38460844_24529.cpp:32:32: error: 'prefix' function uses 'auto' type specifier without trailing return type
     auto prefix(const string &s)
                                ^
0_0_38460844_24529.cpp:32:32: note: deduced return type only available with -std=c++1y or -std=gnu++1y
0_0_38460844_24529.cpp:46:32: error: 'suffix' function uses 'auto' type specifier without trailing return type
     auto suffix(const string &s)
                                ^
0_0_38460844_24529.cpp:46:32: note: deduced return type only available with -std=c++1y or -std=gnu++1y