Compilare: user.cpp: In function ‘void r(int&)’: user.cpp:20:50: 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, sizeof( buff ), fin ); ^ user.cpp:27:50: 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, sizeof( buff ), fin ); ^ user.cpp: In function ‘int main()’: user.cpp:124:42: 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, sizeof( buff ), fin ); ^