/in/calc.cpp:16:13: error: use of undeclared identifier 'RPN'
            RPN(input, list);
            ^
/in/calc.cpp:140:31: error: use of undeclared identifier 'str'
                if (i == 0 && str[0] == '-')
                              ^
2 errors generated.
/in/Compile/Makefile:44: recipe for target 'buildCalc' failed
make: *** [buildCalc] Error 1