Compilare: user.cpp: In function ‘void prefix()’: user.cpp:32:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<strlen(s1);i++) ^ user.cpp: In function ‘int main()’: user.cpp:74:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) ^ user.cpp:72:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.out","w",stdout); ^