Compilare: user.cpp: In function ‘int main()’: user.cpp:213:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<V.size();++i) ^ user.cpp:234:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<V.size();++i) ^ user.cpp:153:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eq.in","r",stdin); ^ user.cpp:154:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eq.out","w",stdout); ^ user.cpp:156:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n",&N,&Q); ^ user.cpp:159:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ user.cpp:182:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ /tmp/ccVEp0Ca.o: In function `main': user.cpp:(.text.startup+0x81): warning: the `gets' function is dangerous and should not be used.