HQ9+ facts for kids

HQ9+ is a special kind of programming language that was created by Cliff L. Biffle in 2001. It's not like the languages people use to build apps or websites. Instead, HQ9+ is known as a "joke" or "esoteric" programming language. This means it was made more for fun and to explore unusual ideas, rather than for serious computer tasks.

What is HQ9+?

HQ9+ is super simple because it only has four basic commands, which are called "operations." When you write a program in HQ9+, you just use these four letters or symbols. Each one tells the computer to do something very specific.

The "H" Operation

The first operation is `H`. If you write `H` in your HQ9+ program, the computer will print the words "Hello, world!" on the screen. Printing "Hello, world!" is a very common first step for people learning a new programming language. It's a simple way to make sure your program is working.

The "Q" Operation

Next up is `Q`. When you use `Q` in your program, it tells the computer to print out the entire program code itself. Imagine writing `Q` and then the computer shows you `Q` back! This type of program, which prints its own code, is sometimes called a quine. It's a clever trick in computer science.

The "9" Operation

The `9` operation is a bit different. If you include `9` in your HQ9+ code, the computer will print out all the lyrics to the song "99 Bottles of Beer". This is a very long and repetitive song, so it shows how a simple command can make the computer do a lot of work!

The "+" Operation

Finally, there's the `+` operation. This command does something called "adding one to the accumulator". An accumulator is like a secret counter inside the program. Every time you use `+`, this hidden counter goes up by one. The tricky part is that you can't actually see what number the accumulator is holding. You can only make it go up! This makes the `+` operation a bit mysterious and adds to the joke nature of the language.

Why is HQ9+ a Joke Language?

HQ9+ is considered a joke language because it's not useful for building real-world software. It can't do complex math, store information, or interact with users in many ways. Its purpose is to be funny and to make programmers think about what makes a language "useful" or "complete." It highlights how even with very few commands, you can still create a "program."

• HQ9+ on Esolang, the esoteric programming languages wiki