Compilare: user.cpp: In function ‘int main()’: user.cpp:18:25: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘std::string* {aka std::basic_string<char>*}’ [-Wformat=] scanf("%s %s", &s1, &s2); ^ user.cpp:18:25: warning: format ‘%s’ expects argument of type ‘char*’, but argument 3 has type ‘std::string* {aka std::basic_string<char>*}’ [-Wformat=] user.cpp:28:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s1.size(); i++) ^ user.cpp:41:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s1.size(); i++) ^ user.cpp:50:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = s1.size(); i < s2.size(); i++) ^ user.cpp:59:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); i++) ^ user.cpp:17:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.in", "r", stdin); ^ user.cpp:18:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s %s", &s1, &s2); ^