Compilare: user.cpp: In function ‘void read()’: user.cpp:12:31: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a+1,sizeof(a),stdin); m=strlen(a+1)-1; ^ user.cpp:13:31: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s+1,sizeof(s),stdin); n=strlen(s+1)-1; ^ user.cpp: In function ‘int main()’: user.cpp:49:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("beep.in","r",stdin); ^ user.cpp:50:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("beep.out","w",stdout); ^ In file included from /usr/include/stdio.h:934:0, from user.cpp:1: In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘void read()’ at user.cpp:12:31: /usr/include/i386-linux-gnu/bits/stdio2.h:253:58: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [enabled by default] return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^ In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘void read()’ at user.cpp:13:31: /usr/include/i386-linux-gnu/bits/stdio2.h:253:58: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [enabled by default] return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^