/in/calc.cpp:55:13: error: use of undeclared identifier 'readTwoOperands'
            readTwoOperands(numStack, firstOperand, secondOperand);
            ^
/in/calc.cpp:88:13: error: use of undeclared identifier 'readTwoOperands'
            readTwoOperands(numStack, firstOperand, secondOperand);
            ^
2 errors generated.
/in/Compile/Makefile:44: recipe for target 'buildCalc' failed
make: *** [buildCalc] Error 1