Compilare: user.cpp: In function ‘int main()’: user.cpp:164:9: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp: In constructor ‘Reader::Reader(const char*)’: user.cpp:26:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^ user.cpp: In member function ‘void Reader::advance()’: user.cpp:51:39: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^