Compilare: user.cpp: In function ‘int main()’: user.cpp:36:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < urm[a].size(); i++) { ^ user.cpp:42:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < sol.size(); i++) ^ user.cpp:44:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < sol.size(); i++) ^ user.cpp:16:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:17:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("semne3.in", "r", stdin); ^ user.cpp:18:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("semne3.out", "w", stdout); ^ user.cpp:19:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:20:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(c + 1); ^ /tmp/cc7CCSFI.o: In function `main': user.cpp:(.text.startup+0x6a): warning: the `gets' function is dangerous and should not be used.