View Compilation Error

0_0_13530676_6030.cpp: In function 'int main()':
0_0_13530676_6030.cpp:55:19: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
         if (op == 'Q')
                   ^
0_0_13530676_6030.cpp:57:24: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
         else if (op == 'U')
                        ^