What is 'hello, world'?

This small and simple program presents a short text when executed and is very useful for multiple reasons.

• Introduce syntax for a specific language
• Verify that your development environment works - editor, interpreter, or compiler-linker
• Feel-good - once executed your code, you know you've successfully created and executed your first program!

Examples

main( ) {
   extrn a, b, c;
   putchar(a); 
   putchar(b); 
   putchar(c); 
   putchar('!*n');
}
a 'hell';
b 'o, w';
c 'orld';

#include <stdio.h>
 
int main(void)
{
    printf("hello, world\n");
    return 0;
} 

  echo "hello, world";

document.write('hello, world');

The first known from 1972 is from Brian Kernighan's Tutorial Introduction to the Language B (a predecessor to C).

As you can see, the syntax varies a lot between the different languages.

• putchar() function in B
• printf() function in C, which is imported (the #include statement) from a library.
• echo method in PHP
• document.write() function in JavaScript

Learning programming languages means learning not only the specific syntax but also what libraries are available. You certainly don't want to write everything from scratch, but reuse other programmers' code as much as possible.

Try for Your Self

Ok, enough of reading - let's to some practicing! Remember - learning by doing.

1. If not already opened, open the Workbench 3L - Your Personal Lab
2. Write your program in the left text area

   document.write('hello, world');

3. Press button to execute (run) your code
4. If you see 'hello, world' in the output area, you've successfully executed your first program. Congratulations!

Debugging, Troubleshooting

If you don't see 'hello, world':

• Make sure your web browser allows execution of JavaScript. All web browsers can run JavaScript but some may have it disabled. (Use Google to troubleshoot.).
• Did you type the code exactly as above. Including single - or double - quotes around the 'hello, world' text.

References

• wikipedia.org/wiki/Hello_world_program
• www.helloworldexample.net/
• google.com/search?q=hello%2C+world