Hello World, the simplest C language!

1. Creation and Compilation of C Files

1.1 UsevimWrite files

vim

#include <>
main(){
    printf("Hello World! \n");
}

• 1
• 2
• 3
• 4

AI writing code

1.2 Program Compilation

>gcc hello.c //Compile and generate executable files

• 1

AI writing code

Notice:
(1) Used heregccThe executable file generated in the form is:
(2) If you want to generate an executable file with the name of a custom hello, usegcc -o hello

1.3 Running the program

./a.out		//Execute the file using ./filename

• 1

AI writing code

The running result is:

Hello World！

• 1

AI writing code

2. Procedure Description

2.1 Header File

== #include <> ==
Represents a file, called "header file" in C language, some of which arefunctionProvided for us to use directly. When you need to use some functions when writing a program, you need to add the "header file" corresponding to the function.

2.2 Main function

main()
It is called the main function, it is the default entry function in C language. By default, the system will call the main function in the program first when running the program. In other words, the execution of a program starts with the main function. Generally, the main function in a complete program is necessary.
(1)The () after main represents the parameter list of the function. An empty parameter list () is used here.
(2)The {} after main() is called the function body. The main operation of defining a function is the work that the function needs to do.
(3) printf("hello world\n"); is a C language execution command, called a statement, and each statement ends with an English semicolon ";". The main function is to print hello world on the screen. where printf() is a print function, which is defined in the header file.
A sentence is equivalent to a sentence in Chinese, but in Chinese it ends with a period "."
(4) printfA piece of text wrapped in function brackets using double quotes " , is called a string, here is what needs to be output in the terminal.
(5) \nIt is a newline character, mainly after printing hello world.

3. Comments

The text used in the code is for explanation, and the text not used for execution is comment.
(1) Use//Make single-line comments

// Single line comment

• 1

AI writing code

(2) Use/* Comment content*/Make multiple lines of comments

/*
 many
 OK
 Note
 release
 */

• 1
• 2
• 3
• 4
• 5
• 6

AI writing code