[Daily C 4] C # preprocessing

C Language # preprocessing of daily C sortingEvery day, I picked up a C-language shell, which grew up and formed thousands of miles.
Today's shell: pre-processing, also called pre-compilation, is the first step for the source code to execute .exe.1.File Inclusion:# Include <> and # include "", for example, # include <stdio. h>. The content of stdio. h file is used for preprocessing.2. macro expansion: # define-defined macros. Preprocessing expands macro references in the source program file into corresponding macro definitions.3. Conditional compilation: # If {}# ifdef and other Conditional compilation commands, pre-processing based on the judgment conditions include part or exclusion part.
 Summary: C compilation has four processes: preprocessing, compilation, assembly, and link. Preprocessing only processes source files at the text level and does not involve content operations. Therefore, there is no difference between variables and functions. Of course, errors at the syntax level are not prompted.Have a nice day!