C Language: Macro definition

C Language Program Run Order: Source code-"compilation preprocessing-" Compile-"link-" Run

Compile pre-processing directives: parsing instructions before compiling

Compiling pre-processing directives

1, macro definition #define

1.1 macro definition with no parameters

1.2 Macro definition with parameters

2. Conditional compilation

3. The file contains #include

Compile pre-processing directives:

1. All compilation pre-processing instructions are preceded by #

2, all compile pre-processing instructions are not required semicolon

Macro definition without parameters: The value following the macro name will be replaced where the macro name is identified at the time of precompilation

Note the point:

1. Macro names in comments are not replaced

2. Macro names that appear in strings are not replaced

C Language: Macro definition