Compilare: user.cpp: In function ‘int main()’: user.cpp:57:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:57:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:71:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:71:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:86:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:86:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:101:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:101:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size()&&j<gy[val].size(); ++j) ^ user.cpp:17:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.in","r",stdin); ^ user.cpp:18:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.out","w",stdout); ^ user.cpp:20:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d\n",&n,&m,&w,&h); ^ user.cpp:23:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:41:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/cctLyTHk.o: In function `main': user.cpp:(.text.startup+0x9a): warning: the `gets' function is dangerous and should not be used.