Compilare: main.cpp: In function 'int addOrSub(std::__cxx11::string, int&)': main.cpp:23:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (position < input.size() && (input[position] == '+' || input[position] == '-')) ~~~~~~~~~^~~~~~~~~~~~~~ main.cpp: In function 'int factor(std::__cxx11::string, int&)': main.cpp:42:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (position < input.size() && (input[position] == '*' || input[position] == '/')) ~~~~~~~~~^~~~~~~~~~~~~~ main.cpp: In function 'int term(std::__cxx11::string, int&)': main.cpp:69:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (position < input.size() && '0' <= input[position] && input[position] <= '9') ~~~~~~~~~^~~~~~~~~~~~~~