Usage of preprocessing symbols # and ## in C language

Usage of preprocessing symbols # and ## in C language

The preprocessor is a part of the C language compiler, which is used to process the source code before compilation. Preprocessor directives begin with a pound sign (#), which includes special symbols such as # and ##. This article will introduce the usage of these two symbols in C language in detail, and illustrate it through sample code.

1. Usage of the # symbol
   In C language, the # symbol is used to convert macro parameters into strings. This is very useful when writing generic code and debugging. Here is an example:

#include <stdio.h>

#define STRINGIFY(x) #x

int main()