/in/calc.cpp:153:37: error: '&&' within '||' [-Werror,-Wlogical-op-parentheses]
        if(input == "-" || input[0] != '-' && !(input[0] >= '0' && input[0] <= '9')) {
                        ~~ ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/calc.cpp:153:37: note: place parentheses around the '&&' expression to silence this warning
        if(input == "-" || input[0] != '-' && !(input[0] >= '0' && input[0] <= '9')) {
                                           ^
                           (                                                       )
1 error generated.
/in/Compile/Makefile:44: recipe for target 'buildCalc' failed
make: *** [buildCalc] Error 1