232:
You MUST NOT use bool type...
- bool is not standard C/C++ type
You are misinformed. bool is a standard C/C++ type. (In C you have to #include <stdbool.h>, but the type is available as _Bool even if stdbool.h is not included. In C++ it's not necessary to include stdbool.h.)
232:
2. HIGH or LOW is also not C/C++ standard
No, but HIGH and LOW are defined in the Arduino environment, so they're perfectly valid to use in an Arduino program.