memory.cpp: In function 'void play()':
memory.cpp:9:12: warning: array subscript has type 'char' [-Wchar-subscripts]
         b[i] = c[i] = 0;
            ^
memory.cpp:9:19: warning: array subscript has type 'char' [-Wchar-subscripts]
         b[i] = c[i] = 0;
                   ^
memory.cpp:14:18: warning: array subscript has type 'char' [-Wchar-subscripts]
         if(b[a[i]]) c[a[i]] = i;
                  ^
memory.cpp:14:27: warning: array subscript has type 'char' [-Wchar-subscripts]
         if(b[a[i]]) c[a[i]] = i;
                           ^
memory.cpp:15:20: warning: array subscript has type 'char' [-Wchar-subscripts]
         else b[a[i]] = i;
                    ^
memory.cpp:19:19: warning: array subscript has type 'char' [-Wchar-subscripts]
         faceup(b[i]), faceup(c[i]);
                   ^
memory.cpp:19:33: warning: array subscript has type 'char' [-Wchar-subscripts]
         faceup(b[i]), faceup(c[i]);
                                 ^