Key Concepts

Review core concepts you need to learn to master this subject

Control Flow

In programming, control flow is the order in which statements and instructions are executed. Programmers are able to change a program’s control flow using control structures such as conditionals.

Being able to alter a program’s control flow is powerful, as it lets us adapt a running program’s behavior depending on the state of the program. For example, suppose a user is using a banking application and wants to withdraw $500. We certainly want the application to behave differently depending on whether the user has $20 or $1000 in their bank account!

Control Flow
Lesson 1 of 2
  1. 1
    How do computers make decisions? Here are a few examples: * Web surfing: Open the browser, load the text, load the images. * Social media: If the user’s profile is private, hide their posts. Other…
  2. 2
    If the user’s profile is private, hide their posts. Otherwise, make them visible. Computers can run instructions on their own, leaving us to work on more interesting and creative problems. But c…
  3. 3
    Repeat a sound four times a measure. Computers are good at repetitive tasks: they exactly follow instructions and perform them quickly. But if the programmer has to write the same instructions f…
  4. 4
    Collect shipping and email address. Reject a purchase if either is incorrect. Errors, or exceptions, happen all the time in programming. You can’t escape them. But you can handle them gracefully…
  5. 5
    Let’s recreate the conditional control structure using JavaScript! (The one about social media posts, remember?) ![Diagram of conditional control structure](https://content.codecademy.com/progra…
  6. 6
    Well done! Control flow is a fundamental concept in programming, and learning the basics will serve you wherever your path leads, regardless of language or domain. In review: - Control flow is t…