Compilare: user.cpp: In function ‘int main()’: user.cpp:69:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,l,p; ^ user.cpp:69:13: warning: unused variable ‘l’ [-Wunused-variable] int i,j,l,p; ^ user.cpp:69:15: warning: unused variable ‘p’ [-Wunused-variable] int i,j,l,p; ^ user.cpp: In member function ‘void instream::advance()’: user.cpp:39:48: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,SIZE,1,input_file); ^ user.cpp: In constructor ‘instream::instream(const char*)’: user.cpp:13:44: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,SIZE,1,input_file); ^