Compilare: user.cpp: In function ‘int F()’: user.cpp:18:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++it==MB)fread(BU,1,MB,stdin),it=0; ^ user.cpp:23:30: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(BU,1,MB,stdin),it=0; ^ user.cpp: In function ‘int main()’: user.cpp:39:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("java.in","r",stdin); ^ user.cpp:40:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("java.out","w",stdout); ^