Compilare: main.cpp: In function 'int main()': main.cpp:50:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for(int i = 0; i < expresie.size(); i++) | ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'int realizare_operatie(std::stack<int>&, std::stack<char>&)': main.cpp:45:12: warning: 'rezultat' may be used uninitialized [-Wmaybe-uninitialized] 45 | return rezultat; | ^~~~~~~~ main.cpp:28:9: note: 'rezultat' was declared here 28 | int rezultat; | ^~~~~~~~