Compilare: user.cpp: In function ‘void read()’: user.cpp:15: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:41: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long long int’ user.cpp: In function ‘int main()’: user.cpp:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:47: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result In file included from /usr/include/stdio.h:910, from /usr/include/c++/4.4/cstdio:45, from user.cpp:3: In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘void read()’ at user.cpp:15: /usr/include/bits/stdio2.h:253: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer