freeCodeCamp/guide/english/c/hello-world/index.md

title
Hello World C

Hello World

Probably the first line of text that everyone prints out on the console when one begins his/her remarkable journey of this endless programming world. To write on console you can use the function printf() contained in the library include <stdio.h>

#include <stdio.h>

/* Any text in between these two characters is a block comment.
   Block comments, unlike inline comments, can span multiple lines.
   Comments are ignored by the compiler and will not be executed.
 */
int main(void)
{
    printf("Hello, World\n");  // text after two slashes '/' are called inline comments.
    return 0;
}

Explanation

• The #include <stdio.h> is a preprocessor directive. This directive tells preprocessor to include the contents of stdio.h (standard input and output) file in this file.
• The stdio.h file contains functions such as scanf() and printf() to take input and display output respectively.
• If you use printf() function without writing #include <stdio.h>, the compiler will generate an error during compliation of the program.
• The execution of a C program starts from the main() function. We write int before it to specify that the program returns a integer value.
• The printf() is a library function to send formatted output to the standard output stream, most commoly the screen. In this program, the printf() displays Hello, World! text on the screen.
• \n is used here to take the cursor to the next line. Hence, if we print anything after this command, it will be printed on a new line.
• The return 0; statement is the "Exit code" of the program. In simple terms, the program ends with this statement or it signifies that function does not return any value.

Output:

Hello, World!

More Information

• Conventionally, the first ever program you write is the "hello world" program, be it in any language.
• This is because Brian Kernighan was the first to write "hello, world" program for the documentation of the BCPL programming language developed by Martin Richards.