style.md

.c

1. system header files
2. user-defined header files
3. constant macro definition
4. function macro definition
5. type definition
6. external function declarations
7. external variable declarations
8. global variable definitions
9. function definitions

global variable definitions

1. basic data type variables
2. library data type variables
3. user-defined struct variables

malloc&free

1. release the memory in the allocating scope