Compilare: user.cpp: In function ‘int main()’: user.cpp:26:28: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {fread(buff,1,100000,stdin); ^ user.cpp:27:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perm2.out","w",stdout); ^ user.cpp: In function ‘void read(int&)’: user.cpp:9:96: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {while(buff[pos]<'0' || buff[pos]>'9') if(++pos==100000) fread(buff, 1, 100000, stdin), pos = 0; ^ user.cpp:14:59: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++pos == 100000) fread(buff, 1, 100000, stdin), pos = 0; ^