Compilare: user.cpp: In function ‘void subsecv(std::string, std::string)’: user.cpp:14:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); i++) ^ user.cpp:16:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0 ; j < b.size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:53:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (poz <0 || poz>=v[i].size()) { ^ user.cpp:58:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i == n && it->size() > sol){ ^ user.cpp:65:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (it->size() > sol){ ^