Introduction to the basic structure of C Language

Introduction to the basic structure of C Language

1. The main function is a program entry. A program can only have one main () function, and an integer return value is required. (In fact, the return value int can be omitted, but this does not mean that the return value is not, the default value is int. We can also not provide return in the main () function, because the C language syntax is not strict enough );

 

2. # include is a pre-processing command used to include a specified file (which must be processed before compilation). The actual task is to copy the corresponding file to the specified location; the content can be any type of file, not just. h file;

 

3. The above showMessage function must be written on the main () function. If it is written below, it must be declared before the main () function;

 

Note: # There are two methods to include files: <> and "". The difference is that <> contains only the compiler library function file, so it is applicable to include library functions. "" contains the current directory of the program first. If not, it searches for the library function path, this applies to custom files;