Compilare: main.cpp: In function 'int main()': main.cpp:37:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | while (index < str.size()) { | ~~~~~~^~~~~~~~~~~~ main.cpp:109:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 109 | for (int i = 0; i < exprPol.size(); i++) { | ~~^~~~~~~~~~~~~~~~