View Compilation Error

0_0_37508889_24425.cpp: In function 'std::string changto16(ll, ll, char, char)':
0_0_37508889_24425.cpp:54:19: error: 'A' was not declared in this scope
   num = -num1 + -+A -A
                   ^
0_0_37508889_24425.cpp:55:2: error: unable to find numeric literal operator 'operator""A'
 +1A 12
  ^
0_0_37508889_24425.cpp:55:2: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes