Shallow and first code

C Language is a high level language ,

low-level     machine language   Binary system
         01000100010001
          assembly language   Mnemonic symbol
         10010   Add   add
         B Language
  senior    C Language   C++  java  python...

     C Language is good at low-level development , Of course, it can also be used for other development
      Standard grammar ANSIC, among C 89/90 Is the most commonly used , also C99,C11,C17...

      Editor used by editor VS2019-- Integrated development environment
      Editor + compiler + The debugger

      stay C What is created in a language is usually .c.h The file of
     .c-- Source file
     .h-- The header file

    How to write the first source file ？
     1. compiler VS2019
     2. Create project
     3. Create the source file
     4. Write code
     5. compile + link + function  ctrl+f5(+fn)

 

    To write code, first write the main function
      Mainstream writing
     int main（）{
     return0;
 }
      Old fashioned writing , Rarely used
     void main() {

 }
int main(void) Express main The function does not require any arguments
int main(int argc,char* argv[])
{} Inside is the function body
return0 And int-- Shaping correspondence ,0 Is an integer , The return value is 0

The use of library functions should include the corresponding header file #inclide<stdio.h>
std-i-o The standard input Output header file
std--standard
i--input
o--output