Preprocessor are one step before the actual compilation. It does works like removing the comments ensuring there are new lines at the file end. It has one important work of processing #include preprocessor directive. Preprocessor directives are instructions that start with # symbol and ends with a new line. These directives tell the preprocessor to perform some text manipulation.

Some of the preprocessor directives are:

  1. include directive
  2. define directive
  3. conditional directive

References

  1. https://www.learncpp.com/cpp-tutorial/introduction-to-the-preprocessor/