Compilare: user.cpp: In function ‘void mark_match(const string&, const string&, std::vector<int>&)’: user.cpp:20:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < pat.size(); ++i) { ^ user.cpp:27:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < str.size(); ++i) { ^ user.cpp:32:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s + 1 == pat.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:52:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < str.size(); ++i) ^