View Compilation Error

0_0_23553210_19613.cpp: In function 'int main()':
0_0_23553210_19613.cpp:68:7: error: 'res' was not declared in this scope
       res = bc - ac;
       ^
0_0_23553210_19613.cpp:72:4: error: 'res' was not declared in this scope
    res = 12 + ac - bc;
    ^
0_0_23553210_19613.cpp:74:17: error: 'res' was not declared in this scope
   printf("%d\n",res);
                 ^