People write programs; programs push bits around. Today you write one. It will be short, and it will run.
2
The Hook
"Make a sandwich."Try giving that instruction to someone who has decided to follow it exactly, with no common sense whatsoever. They will pick up the whole jar. They will put the bread on top of the bag. A computer is that person, every single time, at a billion instructions per second.
3
The Idea
A program is a list of instructions a machine follows in order. It does not guess what you meant. It does not notice that a step is obviously wrong. It does exactly what you wrote, immediately, and the result is either what you wanted or a very fast mistake.
That sounds like a weakness. It is actually the whole point: because the machine is perfectly literal, a program that works once works every time, on any machine, forever.
Your job as a programmer is not to be clever. It is to be unambiguous.
One thing to know now, so it is not a surprise in April: the AP exam does not use Python. It uses a made-up language called AP Pseudocode that no computer actually runs. You will write Python all year and read pseudocode all year, side by side, until switching between them is automatic.
Here is the same three-line program in both. You do not need to understand it — just notice they say the same thing:
Python
name = input("Your name? ")
greeting = "Hi, " + name
print(greeting)
AP Pseudocode
name ← INPUT()
greeting ← "Hi, " + name
DISPLAY(greeting)
Different punctuation, identical idea. That is the entire relationship between them.
4
Try It
Get Python running, then break it
Today's goal is it runs on my machine — not understanding. Follow the setup steps, then type this in and run it:
print("Hello, Mr. Muller's class")
Once that works, change things on purpose:
Change the words inside the quotes. Run it again.
Delete one quotation mark. Run it. Read the error message.
Put the quotation mark back. Run it.
That middle step matters more than the other two. You will see that error a thousand times this year, and today is the day it costs you nothing.
If the setup fights you — say so immediately, do not sit quietly. There is a browser-based backup that needs no installation, and nobody is leaving today without having run a program.
5
Vocabulary
You only need to recognize these today. Every one gets taught properly later.
programrecognition
A list of instructions a computer follows in order.
coderecognition
The text you write that makes up a program.
algorithmrecognition
A recipe: a step-by-step method for getting something done.
6
Think About It
Before you go
What exactly did the error message say when you deleted the quote? Write it down word for word.
The computer did not say “you forgot a quote.” Why do you think it could not just tell you that?
Sign in first if you want Mr. Muller to see it.
7
Connections
Came from 0.2 — your program moves bits. Now you are the one deciding which ones.
Units 2 and 3 — four months of exactly this. Everything you build later starts here.
Unit 9 — the Create Performance Task, where you write a program of your own and the exam asks you about it.
Every code example on this site — shown in both Python and AP Pseudocode, starting now.