Compilare: user.cpp: In function ‘void stringConversion(std::string&)’: user.cpp:24:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); ++i) { ^ user.cpp: In function ‘void dfs(int)’: user.cpp:33:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[node].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:162:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < files.size(); ++i) { ^ user.cpp:172:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < files.size(); ++i) { ^ user.cpp:41:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("links.in", "r", stdin); ^ user.cpp:42:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("links.out", "w", stdout); ^ user.cpp:45:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:53:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(linie); ^ user.cpp:68:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(linie + 1); ^ /tmp/cc2PmWy7.o: In function `main': user.cpp:(.text.startup+0xbb): warning: the `gets' function is dangerous and should not be used.