Compilare: user.cpp: In function ‘void do_it()’: user.cpp:121:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < aux.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:132:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("egal.in","r",stdin); ^ user.cpp:133:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("egal.out","w",stdout); ^ user.cpp:135:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:137:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ user.cpp:141:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= n; i++) scanf("%d", &key[i]); ^