Compilare: user.cpp: In function ‘void eliminare_fraieri()’: user.cpp:79:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (vecini[i].size() < k) ^ user.cpp:89:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (!eliminat[aux2] && vecini[aux2].size() < k) ^ user.cpp: In function ‘void citire()’: user.cpp:24:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zone2.in","r",stdin); ^ user.cpp:25:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zone2.out","w",stdout); ^ user.cpp:26:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d\n",&n,&m,&k); ^ user.cpp:28:25: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(sir[i] + 1); ^ In file included from /usr/include/stdio.h:934:0, from /usr/include/c++/4.8/cstdio:42, from user.cpp:1: In function ‘char* gets(char*)’, inlined from ‘void citire()’ at user.cpp:28:25: /usr/include/i386-linux-gnu/bits/stdio2.h:230:28: warning: call to ‘__gets_warn’ declared with attribute warning: please use fgets or getline instead, gets can't specify buffer size [enabled by default] return __gets_warn (__str); ^ /tmp/cc7ytfvM.o: In function `citire()': user.cpp:(.text+0x85): warning: the `gets' function is dangerous and should not be used.