Embedded C second learning notes

1.typedef

Create a new name for a new data type , It can simplify the definition of variables .

In embedded , Often use typedef Define the structure and enumeration system

2. Structure struct { }

The general structure ：struct Structure name

                 {  Type name 1 member 1;

                    Type name 2 member 2;

                    .............

                    Type name n member n

                  };

3. Macro definition #define

Global parameter definition , Can define basic operation rules

4. Conditional compilation

（1） Select compilation , That is, compile selectively at compile time , Not all statements will be compiled , Compile only the statements that meet the conditions

#if （）

******

#endif

（2） The header file can be defined without repeated compilation

#ifndef