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

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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");  // lines starting with double forward-slash are called inline comments..
    return 0;
}

Explanation

• The #include <stdio.h> is a preprocessor command. This command tells compiler to include the contents of stdio.h (standard input and output) file in the program.
• The stdio.h file contains functions such as scanf() and print() to take input and display output respectively.
• If you use printf() function without writing #include <stdio.h>, the compiler will generate an error during compilation of the program.
• The execution of a C program starts from the main() function.
• The printf() is a library function to send formatted output to the screen. In this program, the printf() function displays "Hello, World!" text on the screen.
• The return 0; statement is the "Exit status" of the program. In simple terms, program ends with this statement.

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.