Compilare: main.cpp: In function 'int main()': main.cpp:25:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | for (int i=0; i<t.length(); i++) | ~^~~~~~~~~~~ main.cpp:63:22: warning: comparison of integer expressions of different signedness: 'std::stack<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 63 | if (stiva.size() < m) | ~~~~~~~~~~~~~^~~