Compilare: main.cpp: In function 'int main()': main.cpp:31:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | for (int j = 0; j < prime.size() && act; ++j) { | ~~^~~~~~~~~~~~~~ main.cpp:42:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 42 | for (int i = 0; i < prime.size(); ++i) { // calculate | ~~^~~~~~~~~~~~~~ main.cpp:50:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for (int j = 0; j < divisors[i].size(); ++j) { // for all its divisors | ~~^~~~~~~~~~~~~~~~~~~~