What Is Programming?

In the previous lesson, you ran a Python program before we stopped to define one. Now we can put names to what you saw.

Programs and programming

A program is a set of instructions written for a computer. Programming is the work of deciding what those instructions should do, writing them clearly, and correcting them when the result is not what you expected.

The instructions are written as code. Code is text that follows the rules of a programming language. In this course, that language is Python.

For now, there are four useful words to remember:

• Program: The complete set of instructions.

• Code: The text used to write those instructions.

• Instruction: One action that Python should carry out.

• Output: Information produced when the program runs.

Here is the basic path from an idea in the editor to a result on the screen:

That final possibility matters. A program does not always produce the output you wanted. Sometimes it produces an error instead. Both results give you information.

Instructions run in order

In a small program like the one below, Python normally starts with the first line and then moves downward.

Before running this example, read the code and predict the output:

print("Morning")
print("Afternoon")
print("Evening")

Now experiment with the same idea:

Move the third line to the top and press Run. Then repeat one of the lines and run it again. Use Reset code when you want the original example back.

Python does not decide that First instruction sounds as if it belongs first. It follows the order of the code.

Code and output are different

When you run print("Hello"), the code is:

print("Hello")

The output is:

Hello

The quotation marks and parentheses help Python understand the instruction. They are not part of the displayed output.

Programming is a cycle

Writing code is rarely a one-pass activity. You write something, run it, inspect the result, and adjust it. Experienced programmers do this constantly.

Ask Monty for another angle

If the difference between a program, code, an instruction, and output still feels blurry, open Monty and ask:

Explain program, code, instruction, and output using an everyday example.

If the example does not work for you, say so and ask for a different one. This is one of Monty’s most useful features: the lesson stays the same, but the explanation can change.

You can also ask Monty for one extra practice question about code and output.

Complete the three checks in this lesson, then press Next to continue.