Compilare: user.cpp: In function ‘int main()’: user.cpp:74:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a1.size(); ++i) ^ user.cpp:77:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a2.size(); ++i) ^ user.cpp:80:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a3.size(); ++i) ^ user.cpp:7:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rgb.in" ,"r",stdin); ^ user.cpp:8:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rgb.out" ,"w",stdout); ^ user.cpp:11:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d", &t); t ; --t) ^ user.cpp:14:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &r, &g, &b); ^