How to explain programming to a non-programmer? [duplicate]

Do you remember that Bill Cosby routine where he talks about trying to order his kids to do everything they're supposed to do before they go to sleep? From rough memory, "Go into the bathroom. Put the toothpaste on your toothbrush. Brush it all over your teeth. Spit it out. Rinse the brush. Rinse your mouth. Get into the shower. Turn on the water. Stand under the water. Cover yourself with soap. Rinse the soap off."

And then they come back downstairs in sopping-wet pajamas because he didn't tell them to strip before they got into the shower.

Programming is like dealing with a extremely bright, smart-assed child who will do everything you tell him to do. What you want him to do doesn't matter; only what you tell him.

And he speaks his own language, which you're gonna have to learn.

And other people have been telling him to do stuff, too.

• You have to write a novel, and you only have 50 words you can use, although you can define new words if you need them
• You are creating a recipe for a complicated dish for someone who will do exactly what you tell them, without making a mistake, but they've never cooked anything ever and don't know the difference between a pot and a knife.

You take a big problem and you cut it into pieces. Then you cut those pieces into smaller pieces. You repeat this task untill the task is so small that you say:

"I know how I can make the computer do that"

Then repeat for the remaining pieces.

Problem solved.

It's like playing a dozen games of chess in your head at once, while your opponents are playing checkers.

Debugging is even worse.

My standard explanation goes something like this:

People think computers are really smart, but they aren't. A computer's a box with an IQ of 5, that just happens to be very good at crunching numbers very quickly. But it doesn't know how to think or how to reason. All it does is exactly what the program tells it to, without regards for the consequences of its actions. If it had legs, you could program it to jump out the nearest window, and it would do exactly that. Then you'd really see the system crash!

With that in mind, programming is basically about figuring out how to represent real-world problems as numbers for a computer to crunch, and how to explain the issue to a box with an IQ of 5 clearly enough that it will do what you want done.

I write instructions for:

humans to read

and

computers to follow

I don't try to explain what I do. I try to make it sound like a technology sufficiently advanced as to be indistinguishable from magic, leaving people amazed at my mystical ability to greet entire worlds by invoking mystical languages of runes and symbols far beyond their comprehension.

People are impressed. "Tell us again," they say, "how you can see sharp over great distances!"

"Share with us," they beseech me, "the wisdom of pearls!"

It does get awkward when you tell people you're proficient in python and they expect you to be able to talk with their pet snake, but hey- just hiss a bit and they'll be none the wiser. I have very rarely been pursued by an angry mob seeking to burn me as a witch, so I'd say this is a safe strategy and a lot less work than trying to explain the technicalities of the job.

I usually just say

I write knitting recipes.

Most grandmothers understand that this includes

• Strict directions to be followed
• Loops (repeat X times)
• Conditionals (for size L do this, for size S do that)

Maps quite nicely actually.

It's like trying to paint a still picture of a moving scene while someone slaps you about the head.
And keeps moving the canvas around.
And keeps changing the palette.
Whilst wearing rollerskates.
Blindfolded.
Surrounded by a swarm of bees.
Whilst getting happy-slapped.
During an earthquake.

I've answered a similar question in more detail, but the gist is, "Programming is like building a factory or an assembly line."

There's a cute Flash game, called light-Bot, which teaches you, what does instruction, program execution and subroutine means, just while you're playing.

I describe it as telling the computer what to do. You instruct it on how to take certain inputs and produce certain output. It does what you tell it, like a person following a recipe.

I explain it's like the old joke about the shampoo instructions:

Wash.
Rinse.
Repeat.

"Oh no! I'm stuck in the shower forever!"