Compilare: main.cpp: In function 'int build_nr(std::string, int&)': main.cpp:21:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 21 | while (poz < sir.size() && '0' <= sir[poz] && sir[poz] <= '9') | ~~~~^~~~~~~~~~~~ main.cpp: In function 'int termen(std::string, int&)': main.cpp:32:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 32 | if (poz >= sir.size() || sir[poz] == '+') | ~~~~^~~~~~~~~~~~~ main.cpp: In function 'void eval(int, int)': main.cpp:64:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 64 | while (poz < sir.size()) | ~~~~^~~~~~~~~~~~