Compilare: main.cpp: In function 'int main()': main.cpp:79:55: warning: comparison of integer expressions of different signedness: 'std::stack<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 79 | if (st.size() < n2) { | ~~~~~~~~~~^~~~ main.cpp:66:19: warning: unused variable 'ch' [-Wunused-variable] 66 | for (auto ch : s1) { | ^~ main.cpp:90:23: warning: comparison of integer expressions of different signedness: 'std::stack<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 90 | if (st.size() != n2) { | ~~~~~~~~~~^~~~~ main.cpp:40:16: warning: unused variable 'j' [-Wunused-variable] 40 | int i, j, nr, n1, n2; | ^ main.cpp:40:23: warning: variable 'n1' set but not used [-Wunused-but-set-variable] 40 | int i, j, nr, n1, n2; | ^~