#include <stdio.h> // Line 1

int main() // Line 2

{  // Line 3

      printf("Hello World!");  // Line 4

      return 0;  // Line 5

}  // Line 6


Line 1 : #include <stdio.h> is a header file library that lets us work with input and output functions, such as printf(), scanf(). Header files add functionality to C programs.

Line 2 : Another thing that always appear in a C program, is main(). This is called a function. 

Line 3 : Open curly brace. Any code inside its curly braces {} will be executed.

Line 4 : printf() is a function used to output/print text to the screen. In the above program it will output "Hello World!".

NOTE : Every C statement ends with a semicolon ;

Line 5 : return 0 ends the main() function.

Line 6 : Do not forget to add the closing curly brace } to actually end the main function.