Compilare: main.cpp: In function 'void read()': main.cpp:23:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d\n",&n,&m,&q); ^ main.cpp:26:33: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets (buff+1,DIM,stdin); ^ main.cpp: In function 'void query()': main.cpp:99:43: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d",&xi,&yi,&xf,&yf); ^ main.cpp: In function 'int main()': main.cpp:106:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pirati.in","r",stdin); ^ main.cpp:107:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pirati.out","w",stdout); ^ In file included from /usr/include/stdio.h:936:0, from /usr/include/c++/6/cstdio:42, from /usr/include/c++/6/ext/string_conversions.h:43, from /usr/include/c++/6/bits/basic_string.h:5420, from /usr/include/c++/6/string:52, from /usr/include/c++/6/bitset:47, from main.cpp:3: In function 'char* fgets(char*, int, FILE*)', inlined from 'void read()' at main.cpp:26:33: /usr/include/bits/stdio2.h:261:58: warning: call to '__fgets_chk_warn' declared with attribute warning: fgets called with bigger size than length of destination buffer return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^